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Intellectual disability syndromic and non-syndromic v0.6062 CRNKL1 Mark Cleghorn gene: CRNKL1 was added
gene: CRNKL1 was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: CRNKL1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: CRNKL1 were set to complex neurodevelopmental disorder MONDO:0100038
Penetrance for gene: CRNKL1 were set to Complete
Review for gene: CRNKL1 was set to GREEN
Added comment: Unpublished, presented at ESHG June 2024 - Louise Bicknell, University of Otago NZ
8 unrelated families via gene matcher with rare, de novo, missense variants in CRNKL1
severe microcephaly (all, -8 to -11 SD)
ID/epilepsy
pontocerebellar hypoplasia (6/8)
simplified gyration (8/8)
7 variants are missense at p.Arg267 residue
1 variant missense at p.Arg301
RNA-seq on patient fibroblasts - no alteration in gene expression
Zebrafish homolog of Arg267 and Arg301 - mimics observed phenotype (reduced brain development), increased in embryo apoptosis
RNQ seq on affected zebrafish embryos - transcriptome strongly disrupted
Splicing analysis in progress

CRKNL1 supports U6 structure in spliceosome
Sources: Other
Intellectual disability syndromic and non-syndromic v0.6051 PSMF1 Zornitza Stark gene: PSMF1 was added
gene: PSMF1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PSMF1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PSMF1 were set to https://www.medrxiv.org/content/10.1101/2024.06.19.24308302v1
Phenotypes for gene: PSMF1 were set to Complex neurodevelopmental disorder with motor features, MONDO:0100516, PSMF1-related
Review for gene: PSMF1 was set to GREEN
Added comment: 22 individuals from 15 families reported with a range of neurological phenotypes ranging from early-onset Parkinson's disease; childhood conditions typified by ID and a range of movement disorders; through to perinatal lethal presentations with arthrogryposis multiplex. Genotype-phenotype correlation: biallelic missense variants resulted in the milder phenotypes, while bi-allelic LoF variants in the more severe phenotypes. Supportive functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.6049 VPS50 Ain Roesley reviewed gene: VPS50: Rating: GREEN; Mode of pathogenicity: None; Publications: 38876772; Phenotypes: Neurodevelopmental disorder with microcephaly, seizures, and neonatal cholestasis MIM#619685; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.6046 PAK2 Ain Roesley gene: PAK2 was added
gene: PAK2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PAK2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PAK2 were set to 33693784; 38894571; 38712026
Phenotypes for gene: PAK2 were set to Knobloch 2 syndrome MIM#618458
Review for gene: PAK2 was set to GREEN
gene: PAK2 was marked as current diagnostic
Added comment: total of 3 families including 2 siblings with intra-familial variability

Siblings' phenotypes:
Both had retinal detachment and interstitial parenchymal pulmonary changes on chest X-rays, but only one child had additional significant features such as cataract, posterior encephalocele, severe DD/ID with ASD, and epilepsy.

Other 2 pro bands:
GDD, delayed motor (but normal verbal) skills, hypotonia

Missense variants with in vitro functional demonstrating reduction in PAK2 auto phosphorylation
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.6042 MYH10 Zornitza Stark Phenotypes for gene: MYH10 were changed from Microcephaly; Intellectual Disability to AD complex neurodevelopmental disorder with or without congenital anomalies (MONDO:0100465)
Intellectual disability syndromic and non-syndromic v0.6036 PTEN Ain Roesley Phenotypes for gene: PTEN were changed from Cowden syndrome 1 MIM#158350; Macrocephaly/autism syndrome MIM#605309 to Cowden syndrome 1 MIM#158350; Macrocephaly/autism syndrome MIM#605309; PTEN hamartoma tumor syndrome MONDO:0017623
Intellectual disability syndromic and non-syndromic v0.6025 ATXN7L3 Chirag Patel gene: ATXN7L3 was added
gene: ATXN7L3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ATXN7L3 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ATXN7L3 were set to PMID: 38753057
Phenotypes for gene: ATXN7L3 were set to Neurodevelopmental disorder, MONDO_0100500
Review for gene: ATXN7L3 was set to GREEN
gene: ATXN7L3 was marked as current diagnostic
Added comment: This study reports 9 unrelated individuals with de novo heterozygous variants in ATXN7L3 identified through WES testing and GeneMatcher. Core clinical features included: global motor and language developmental delay, hypotonia, and dysmorphic features (hypertelorism, epicanthal folds, blepharoptosis, small nose, small mouth, and low-set posteriorly rotated ears). Variable features included: feeding difficulties, seizures, mild periventricular leukomalacia, and structural cardiac abnormalities.

A recurrent nonsense variant [p.(Arg114Ter)] was found in 5/9 individuals. The other variants were 1 frameshift [p.(Ser112LysfsTer12)] and 3 missense variants [p.(Ile71Thr), p.(Ser92Arg), and p.(Leu106Pro)]. They investigated the effects of the recurrent nonsense variant [p.(Arg114Ter)] in fibroblasts of an affected individual. ATXN7L3 protein levels were reduced, and deubiquitylation was impaired (as indicated by an increase in histone H2Bub1 levels). This is consistent with the previous observation of increased H2Bub1 levels in Atxn7l3-null mouse embryos, which have developmental delay and embryonic lethality.

Pathogenic variants in deubiquitinating enzymes (DUBs) have been implicated in neurodevelopmental disorders (ND) and congenital abnormalities. ATXN7L3 is a component of the DUB module of the SAGA complex, and two other related DUB modules, and serves as an obligate adaptor protein of 3 ubiquitin-specific proteases (USP22, USP27X or USP51).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.6022 FAM177A1 Chirag Patel gene: FAM177A1 was added
gene: FAM177A1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FAM177A1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FAM177A1 were set to PMID: 38767059, 25558065
Phenotypes for gene: FAM177A1 were set to Neurodevelopmental disorder, MONDO_0100500
Review for gene: FAM177A1 was set to GREEN
gene: FAM177A1 was marked as current diagnostic
Added comment: PMID: 38767059
5 individuals from 3 unrelated families reported with with biallelic loss of function variants in FAM177A1. Clinical features included: global developmental delay, intellectual disability, seizures, behavioural abnormalities, hypotonia, gait disturbance, and macrocephaly.

They showed that FAM177A1 localizes to the Golgi complex in mammalian and zebrafish cells. Intersection of the RNA-seq and metabolomic datasets from FAM177A1-deficient human fibroblasts and whole zebrafish larvae demonstrated dysregulation of pathways associated with apoptosis, inflammation, and negative regulation of cell proliferation.

PMID: 25558065
A study of 143 multiplex consanguineous families identified a homozygous frameshift variant in FAM177A1 in 1 family with 4 affected siblings with intellectual disability, dolicocephaly, obesity, and macrocephaly. The variant segregated with all 4 affected siblings and parents were confirmed heterozygous carriers.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.6015 RELN Zornitza Stark reviewed gene: RELN: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Lissencephaly 2 (Norman-Roberts type), MIM# 257320; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.6015 RELN Zornitza Stark Phenotypes for gene: RELN were changed from to Lissencephaly 2 (Norman-Roberts type), MIM# 257320
Intellectual disability syndromic and non-syndromic v0.6013 RELN Tashunka Taylor-Miller changed review comment from: 7 individuals from 4 families with biallelic variants, and 13 individuals from 7 families with monoallelic (heterozygous) variants of RELN and frontotemporal or temporal-predominant lissencephaly variant. Associated features: intellectual disability (16/20), seizures (5/20), unprovoked aggression (6/20), sleep disturbance (7/20)
Variant spectrum includes: loss of function, missense, splice-site variants.

MRI features include: anterior-predominant “thin”lisencephaly pachygyria with cerebellar hypoplasia
Biallelic variants are associated with a severe phenotype that includes cerebellar hypoplasia.
Monoallelic variants are associated with incomplete penetrance and variable expressivity (eg: one adult with abnormal MRI but normal intelligence and neurological profile).; to: 7 individuals from 4 families with biallelic variants, and 13 individuals from 7 families with monoallelic (heterozygous) variants of RELN and frontotemporal or temporal-predominant lissencephaly variant. Associated features: intellectual disability (16/20), seizures (5/20), unprovoked aggression (6/20), sleep disturbance (7/20)
Variant spectrum includes: loss of function, missense, splice-site variants.

MRI features include: anterior-predominant “thin” lisencephaly pachygyria with cerebellar hypoplasia.
Biallelic variants are associated with a severe phenotype that includes cerebellar hypoplasia.
Monoallelic variants are associated with incomplete penetrance and variable expressivity (eg: one adult with abnormal MRI but normal intelligence and neurological profile).
Intellectual disability syndromic and non-syndromic v0.6001 SSR4 Katie Thompson reviewed gene: SSR4: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 24218363, 26264460; Phenotypes: intellectual disabilities, hypotonia, microcephaly, seizures, Feeding problems, Facial dysmorphism, Gastrointestinal abnormalities, Failure to thrive, strabismus; Mode of inheritance: X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Intellectual disability syndromic and non-syndromic v0.5993 SNAP29 Gunjan Garg reviewed gene: SNAP29: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 33977139, 30793783, 29051910; Phenotypes: cerebral dysgenesis, 609528, Global developmental delay, schizencephaly, polymicrogyria, intellectual disability, neurodevelopment delay; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5993 COL4A1 Hali Van Niel reviewed gene: COL4A1: Rating: GREEN; Mode of pathogenicity: None; Publications: 30413629, 33912663, 36786861, 32042920; Phenotypes: COL4A1-related disorder MONDO:0800461, brain small vessel disease 1 with or without ocular anomalies MONDO:0008289, microangiopathy and leukoencephalopathy, pontine, autosomal dominant MONDO:0032814; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5982 CACNA1A Zornitza Stark Phenotypes for gene: CACNA1A were changed from to developmental and epileptic encephalopathy, 42 MONDO:0014917
Intellectual disability syndromic and non-syndromic v0.5949 TBCE Zornitza Stark Phenotypes for gene: TBCE were changed from to Encephalopathy, progressive, with amyotrophy and optic atrophy MIM:617207; Hypoparathyroidism-retardation-dysmorphism syndrome MIM:241410
Intellectual disability syndromic and non-syndromic v0.5928 SCN8A Zornitza Stark Phenotypes for gene: SCN8A were changed from to Developmental and epileptic encephalopathy 13, MIM# 614558
Intellectual disability syndromic and non-syndromic v0.5922 SIX3 Zornitza Stark Phenotypes for gene: SIX3 were changed from to Holoprosencephaly 2, autosomal dominant, MIM#157170
Intellectual disability syndromic and non-syndromic v0.5919 SIX3 Zornitza Stark reviewed gene: SIX3: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Holoprosencephaly 2, autosomal dominant, MIM#157170; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5915 SCN2A Zornitza Stark Phenotypes for gene: SCN2A were changed from to Developmental and epileptic encephalopathy 11, MIM# 613721
Intellectual disability syndromic and non-syndromic v0.5912 BMP4 Zornitza Stark Phenotypes for gene: BMP4 were changed from Microphthalmia, syndromic 6, MIM# 607932 to Microphthalmia, syndromic 6, MIM# 607932
Intellectual disability syndromic and non-syndromic v0.5911 BMP4 Zornitza Stark Phenotypes for gene: BMP4 were changed from to Microphthalmia, syndromic 6, MIM# 607932
Intellectual disability syndromic and non-syndromic v0.5908 BMP4 Zornitza Stark reviewed gene: BMP4: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Microphthalmia, syndromic 6, MIM# 607932; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5908 CDON Zornitza Stark Phenotypes for gene: CDON were changed from to holoprosencephaly 11 MONDO:0013642
Intellectual disability syndromic and non-syndromic v0.5902 CDON Hali Van Niel reviewed gene: CDON: Rating: GREEN; Mode of pathogenicity: None; Publications: 21802063, 26728615, 31502381, 32729136, 26529631; Phenotypes: holoprosencephaly 11 MONDO:0013642; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5884 SERAC1 Zornitza Stark Phenotypes for gene: SERAC1 were changed from to 3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like syndrome (MEGDEL), MIM#614739
Intellectual disability syndromic and non-syndromic v0.5881 SERAC1 Zornitza Stark reviewed gene: SERAC1: Rating: GREEN; Mode of pathogenicity: None; Publications: 24741715, 37711114, 37090937, 28916646, 32684373; Phenotypes: 3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like syndrome (MEGDEL), MIM#614739; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5881 SIX3 Laura Mazurkijevic reviewed gene: SIX3: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 20531442, 19346217, 20157829, 15635066; Phenotypes: Holoprosencephaly 2, autosomal dominant, MIM#157170; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5881 SCN8A Tinashe Nhindiri reviewed gene: SCN8A: Rating: GREEN; Mode of pathogenicity: Other; Publications: PMID: 34353676, 38233770, 30171078; Phenotypes: Epileptic encephalopathy, Developmental delay, Intellectual disability; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5881 TBCE Leanne Baxter reviewed gene: TBCE: Rating: GREEN; Mode of pathogenicity: Other; Publications: PMID:27666369: PMID:17699660: PMID:34356170: PMID: 34134906; Phenotypes: Encephalopathy, progressive, with amyotrophy and optic atrophy MIM:617207, Hypoparathyroidism-retardation-dysmorphism syndrome MIM:241410, Kenny-Caffey syndrome, type 1 MIM:244460; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5880 SLC19A3 Zornitza Stark Phenotypes for gene: SLC19A3 were changed from to Thiamine metabolism dysfunction syndrome 2 (biotin- or thiamine-responsive encephalopathy type 2), MIM# 607483
Intellectual disability syndromic and non-syndromic v0.5878 SLC19A3 Jane Lin changed review comment from: Rare disorder of thiamine metabolism and transport. Has well characterised gene-phenotype link in more than 3 families (multiple publications, in different subpopulations). Many symptoms in this disorder, for example confusion, seizures, ataxia, dystonia, supranuclear facial palsy, external ophthalmoplegia, and dysphagia. ID has been described as a sequela in many cases.; to: Rare disorder of thiamine metabolism and transport. Has well characterised gene-phenotype link for THMD2 in more than 3 families (multiple publications, in different subpopulations). Many CNS related symptoms in this disorder, for example confusion, seizures, ataxia, dystonia, supranuclear facial palsy, external ophthalmoplegia, and dysphagia. ID has been described as a sequela in many cases.
Intellectual disability syndromic and non-syndromic v0.5877 SASS6 Zornitza Stark gene: SASS6 was added
gene: SASS6 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: SASS6 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SASS6 were set to 24951542; 30639237
Phenotypes for gene: SASS6 were set to Microcephaly 14, primary, autosomal recessive, MIM# 616402
Review for gene: SASS6 was set to GREEN
Added comment: At least 3 unrelated families reported, severe ID is part of the phenotype.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.5812 CASK Zornitza Stark Added comment: Comment when marking as ready: Microcephaly with pontine and cerebellar hypoplasia (MICPCH), generally associated with pathogenic loss-of-function variants in CASK
X-linked intellectual disability (XLID) with or without nystagmus, generally associated with hypomorphic CASK pathogenic variants
Intellectual disability syndromic and non-syndromic v0.5812 CASK Zornitza Stark Phenotypes for gene: CASK were changed from to FG syndrome 4 MIM#300422; Intellectual developmental disorder and microcephaly with pontine and cerebellar hypoplasia MIM#300749; Intellectual disability, with or without nystagmus MIM#300422
Intellectual disability syndromic and non-syndromic v0.5796 GLUL Zornitza Stark Phenotypes for gene: GLUL were changed from Developmental and epileptic encephalopathy, MONDO:0100062, GLUL-related; Glutamine deficiency, congenital MIM#610015 to Glutamine deficiency, congenital MIM#610015; Developmental and epileptic encephalopathy 116, MIM# 620806
Intellectual disability syndromic and non-syndromic v0.5795 GLUL Zornitza Stark edited their review of gene: GLUL: Changed phenotypes: Glutamine deficiency, congenital MIM#610015, Developmental and epileptic encephalopathy 116, MIM# 620806
Intellectual disability syndromic and non-syndromic v0.5792 NOTCH3 Ain Roesley Phenotypes for gene: NOTCH3 were changed from neurodevelopmental disorder MONDO:0700092, NOTCH3-related; Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310 to neurodevelopmental disorder MONDO:0700092, NOTCH3-related; Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310
Intellectual disability syndromic and non-syndromic v0.5791 NOTCH3 Ain Roesley Phenotypes for gene: NOTCH3 were changed from Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310 to neurodevelopmental disorder MONDO:0700092, NOTCH3-related; Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310
Intellectual disability syndromic and non-syndromic v0.5790 NOTCH3 Ain Roesley changed review comment from: Pre-print (https://sciprofiles.com/publication/view/62eb776390415f0166f73fae7cd172ed)

Review of research and diagnostic databases and literature review found 50 individuals from 31 families with biallelic variants.

13 PTCS (including splice) and 15 missense resulting in gain or loss of Cys residue.

AR PTCs are associated with early onset leukoencephalopathy including cognitive decline, dev delay/ID and dysmorphism

AR missense are associated with CADASIL-like phenotype; to: Pre-print (https://sciprofiles.com/publication/view/62eb776390415f0166f73fae7cd172ed)

Review of research and diagnostic databases and literature review found 50 individuals from 31 families with biallelic variants.

13 PTCS (including splice) and 15 missense resulting in gain or loss of Cys residue.

AR PTCs are associated with early onset leukoencephalopathy including cognitive decline, dev delay/ID and dysmorphism; seizures, spasticity, hypotonia, ataxia

AR missense are associated with CADASIL-like phenotype
Intellectual disability syndromic and non-syndromic v0.5778 IQSEC2 Ain Roesley Phenotypes for gene: IQSEC2 were changed from Intellectual developmental disorder, X-linked 1 MIM#309530, MONDO:0010656; Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347 to Intellectual developmental disorder, X-linked 1 MIM#309530, MONDO:0010656; Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347
Intellectual disability syndromic and non-syndromic v0.5778 IQSEC2 Ain Roesley Phenotypes for gene: IQSEC2 were changed from Mental retardation, X-linked 1/78, MIM# 309530, MONDO:0010656; Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347 to Intellectual developmental disorder, X-linked 1 MIM#309530, MONDO:0010656; Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347
Intellectual disability syndromic and non-syndromic v0.5773 SNF8 Zornitza Stark Phenotypes for gene: SNF8 were changed from Developmental and epileptic encephalopathy 115, MIM#620783 to Developmental and epileptic encephalopathy 115, MIM#620783; Neurodevelopmental disorder plus optic atrophy, MIM# 620784
Intellectual disability syndromic and non-syndromic v0.5772 SNF8 Zornitza Stark edited their review of gene: SNF8: Changed phenotypes: Developmental and epileptic encephalopathy 115, MIM#620783, Neurodevelopmental disorder plus optic atrophy, MIM# 620784
Intellectual disability syndromic and non-syndromic v0.5769 SNF8 Zornitza Stark Phenotypes for gene: SNF8 were changed from Neurodevelopmental disorder (MONDO:0700092), SNF8-related to Developmental and epileptic encephalopathy 115, MIM#620783
Intellectual disability syndromic and non-syndromic v0.5768 SNF8 Zornitza Stark reviewed gene: SNF8: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 115, MIM#620783; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5760 GLUL Zornitza Stark Phenotypes for gene: GLUL were changed from to Developmental and epileptic encephalopathy, MONDO:0100062, GLUL-related; Glutamine deficiency, congenital MIM#610015
Intellectual disability syndromic and non-syndromic v0.5757 GLUL Zornitza Stark reviewed gene: GLUL: Rating: GREEN; Mode of pathogenicity: None; Publications: 16267323, 21353613, 33150193; Phenotypes: Developmental and epileptic encephalopathy, MONDO:0100062, GLUL-related, Glutamine deficiency, congenital MIM#610015, disorder of amino acid metabolism; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5754 DISP1 Zornitza Stark Phenotypes for gene: DISP1 were changed from Holoprosencephaly, MONDO:0016296 to Holoprosencephaly (MONDO:0016296), DISP1-related
Intellectual disability syndromic and non-syndromic v0.5750 DISP1 Zornitza Stark edited their review of gene: DISP1: Added comment: PMID: 38529886
25 individuals from 20 unrelated families with a phenotype associated with mild holoprosencephaly (HPE).
A total of 23 different variants were identified in DISP1 (missense, frameshift and nonsense).
14 heterozygous individuals , 5 compound heterozygous individuals, 6 homozygous individuals (5 of the individuals were from 3 unrelated consanguineous families).

HPE phenotype was also seen prenatally as one of the reported monoallelic individuals was a fetus at 20+6 GW prior to passing due to MTP.; Changed publications: 19184110, 26748417, 23542665, 38529886; Changed phenotypes: Holoprosencephaly (MONDO:0016296), DISP1-related; Changed mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5738 CEP295 Chirag Patel gene: CEP295 was added
gene: CEP295 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CEP295 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CEP295 were set to PMID: 38154379
Phenotypes for gene: CEP295 were set to Seckel syndrome 11, OMIM # 620767
Review for gene: CEP295 was set to GREEN
gene: CEP295 was marked as current diagnostic
Added comment: 4 children from 2 unrelated families with Seckel-like syndrome - severe primary microcephaly, short stature, developmental delay, intellectual disability, facial deformities, and abnormalities of fingers and toes. WES identified biallelic pathogenic variants in CEP295 gene (p(Q544∗) and p(R1520∗); p(R55Efs∗49) and p(P562L)).

Patient-derived fibroblasts and CEP295-depleted U2OS and RPE1 cells were used to clarify the underlying mechanisms. Depletion of CEP295 resulted in a decrease in the numbers of centrioles and centrosomes and triggered p53-dependent G1 cell cycle arrest. Loss of CEP295 caused extensive primary ciliary defects in both patient-derived fibroblasts and RPE1 cells. The results from complementary experiments revealed that the wild-type CEP295, but not the mutant protein, can correct the developmental defects of the centrosome/centriole and cilia in the patient-derived skin fibroblasts.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5729 USP14 Zornitza Stark gene: USP14 was added
gene: USP14 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: USP14 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: USP14 were set to 38469793; 35066879
Phenotypes for gene: USP14 were set to Syndromic disease MONDO:0002254, USP14-related
Review for gene: USP14 was set to AMBER
Added comment: AMBER rating as two of the families had affected fetuses, one had a severely affected newborn, and fourth had a progressive course: none fit well with ID, though there's likely to be a continuum.

PMID 35066879: 3 fetuses from 2 different branches of a consanguineous family, presenting with distal arthrogryposis, underdevelopment of the corpus callosum, and dysmorphic facial features. Exome sequencing identified a biallelic 4-bp deletion (c.233_236delTTCC; p.Leu78Glnfs*11) in USP14, and sequencing of family members showed segregation with the phenotype. Ubiquitin-specific protease 14 (USP14) encodes a major proteasome-associated deubiquitinating enzyme with an established dual role as an inhibitor and an activator of proteolysis, maintaining protein homeostasis. Usp14-deficient mice show a phenotype similar to lethal human multiple congenital contractures phenotypes, with callosal anomalies, muscle wasting, and early lethality, attributed to neuromuscular junction defects due to decreased monomeric ubiquitin pool. RT-qPCR experiment in an unaffected heterozygote revealed that mutant USP14 was expressed, indicating that abnormal transcript escapes nonsense-mediated mRNA decay.

PMID 38469793: biallelic USP14 variants in four individuals from three unrelated families: one fetus, a newborn with a syndromic NDD, and two siblings affected by a progressive neurological disease. Specifically, the two siblings from the latter family carried two compound heterozygous variants c.8T>C p.(Leu3Pro) and c.988C>T p.(Arg330*), while the fetus had a homozygous frameshift c.899_902del p.(Lys300Serfs*24) variant and the newborn patient harbored a homozygous frameshift c.233_236del p.(Leu78Glnfs*11) variant. The fetus and the newborn had extensive brain malformations.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5727 SLC32A1 Zornitza Stark Phenotypes for gene: SLC32A1 were changed from Generalized epilepsy with febrile seizures plus, type 12, MIM# 620755 to Generalized epilepsy with febrile seizures plus, type 12, MIM# 620755; Developmental and epileptic encephalopathy 114, MIM# 620774
Intellectual disability syndromic and non-syndromic v0.5726 SLC32A1 Zornitza Stark reviewed gene: SLC32A1: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 114, MIM# 620774; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5725 SV2A Zornitza Stark Phenotypes for gene: SV2A were changed from Neurodevelopmental disorder, MONDO:0700092, SV2A-related to Neurodevelopmental disorder, MONDO:0700092, SV2A-related; Developmental and epileptic encephalopathy 113, MIM# 620772
Intellectual disability syndromic and non-syndromic v0.5724 SV2A Zornitza Stark reviewed gene: SV2A: Rating: AMBER; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 113, MIM# 620772; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5723 SLC32A1 Zornitza Stark Phenotypes for gene: SLC32A1 were changed from developmental and epileptic encephalopathy MONDO:0100062, SLC32A1-related to Generalized epilepsy with febrile seizures plus, type 12, MIM# 620755
Intellectual disability syndromic and non-syndromic v0.5715 SNF8 Elena Savva Phenotypes for gene: SNF8 were changed from Severe developmental delay, epileptic encephalopathy, brain MRI abnormality; intellectual disability, childhood-onset optic atrophy, ataxia to Neurodevelopmental disorder (MONDO:0700092), SNF8-related
Intellectual disability syndromic and non-syndromic v0.5712 SNF8 Chern Lim gene: SNF8 was added
gene: SNF8 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SNF8 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SNF8 were set to 38423010
Phenotypes for gene: SNF8 were set to Severe developmental delay, epileptic encephalopathy, brain MRI abnormality; intellectual disability, childhood-onset optic atrophy, ataxia
Review for gene: SNF8 was set to GREEN
gene: SNF8 was marked as current diagnostic
Added comment: PMID: 38423010
- Nine individuals from six families presenting with a spectrum of neurodevelopmental/neurodegenerative features caused by bi-allelic variants in SNF8. In total, three putative LoF variants and four missense variants were identified.
- The phenotypic spectrum included four individuals with severe developmental and epileptic encephalopathy, massive reduction of white matter, hypo-/aplasia of the corpus callosum, neurodevelopmental arrest, and early death. A second cohort shows a milder phenotype with intellectual disability, childhood-onset optic atrophy, or ataxia. All mildly affected individuals shared the same hypomorphic variant, c.304G>A (p.Val102Ile) as compound heterozygous.
- Functional studies using fibroblasts derived from patients and zebrafish model showed LoF is the disease mech.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5705 CACNA1A Hali Van Niel reviewed gene: CACNA1A: Rating: GREEN; Mode of pathogenicity: None; Publications: 27476654, 33985586; Phenotypes: developmental and epileptic encephalopathy, 42 MONDO:0014917; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5700 HMBS Zornitza Stark edited their review of gene: HMBS: Changed publications: 15534187, 34089223; Changed phenotypes: Encephalopathy, porphyria-related MIM#620704, Leukoencephalopathy, porphyria-related, MIM#620711
Intellectual disability syndromic and non-syndromic v0.5700 HMBS Zornitza Stark gene: HMBS was added
gene: HMBS was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: HMBS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: HMBS were set to 15534187
Phenotypes for gene: HMBS were set to Encephalopathy, porphyria-related MIM#620704; Leukoencephalopathy, porphyria-related, MIM#620711
Review for gene: HMBS was set to GREEN
Added comment: Several families reported with encephalopathy/leukoencephalopathy and ballelic variants in this gene.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.5697 MAX Zornitza Stark Phenotypes for gene: MAX were changed from Syndromic disease (MONDO:0002254), MAX-related to Polydactyly-macrocephaly syndrome, MIM# 620712
Intellectual disability syndromic and non-syndromic v0.5683 SP9 Suliman Khan gene: SP9 was added
gene: SP9 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SP9 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: SP9 were set to PMID: 38288683
Phenotypes for gene: SP9 were set to neurodevelopmental disorder MONDO:0700092
Review for gene: SP9 was set to GREEN
Added comment: PMID: 38288683: reported 5 unrelated patients with de novo heterozygous variants (missense and PTV) in SP9 gene. In silico and in vitro studies suggested a novel form of interneuronopathy with variable severity depending on the presence of loss or gain of function variants. Patients with loss-of-function variants had ID, ASD, and epilepsy, whereas missense variants in the second C2H2 binding domain result in hypomorphic and neomorphic DNA binding functions that cause severe epileptic encephalopathy. The author suggested a novel form of interneuronopathy with variable severity depending on the presence of loss or gain of function variants.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5674 ATP6V0A1 Elena Savva Phenotypes for gene: ATP6V0A1 were changed from Developmental and epileptic encephalopathy 104 MIM#619970; Neurodevelopmental disorder with epilepsy and brain atrophy MIM#619971 to Developmental and epileptic encephalopathy 104 MIM#619970; Neurodevelopmental disorder with epilepsy and brain atrophy MIM#619971
Intellectual disability syndromic and non-syndromic v0.5673 ATP6V0A1 Elena Savva Phenotypes for gene: ATP6V0A1 were changed from Developmental and epileptic encephalopathy 104 MIM#619970; Neurodevelopmental disorder with epilepsy and brain atrophy MIM#619971 to Developmental and epileptic encephalopathy 104 MIM#619970; Neurodevelopmental disorder with epilepsy and brain atrophy MIM#619971
Intellectual disability syndromic and non-syndromic v0.5673 ATP6V0A1 Elena Savva Phenotypes for gene: ATP6V0A1 were changed from Neurodevelopmental disorder, MONDO:0700092, ATP6V0A1-related to Developmental and epileptic encephalopathy 104 MIM#619970; Neurodevelopmental disorder with epilepsy and brain atrophy MIM#619971
Intellectual disability syndromic and non-syndromic v0.5666 PPFIA3 Zornitza Stark gene: PPFIA3 was added
gene: PPFIA3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PPFIA3 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PPFIA3 were set to 37034625
Phenotypes for gene: PPFIA3 were set to Neurodevelopmental disorder, MONDO:0700092, PPFIA3-related
Review for gene: PPFIA3 was set to GREEN
Added comment: 19 individuals with mono-allelic variants presenting with features including developmental delay, intellectual disability, hypotonia, micro/macrocephaly, autism, and epilepsy.

One individual with compound het variants: insufficient evidence for bi-allelic variants causing disease.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5661 MAX Rylee Peters gene: MAX was added
gene: MAX was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MAX was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MAX were set to 38141607
Phenotypes for gene: MAX were set to Syndromic disease (MONDO:0002254), MAX-related
Review for gene: MAX was set to GREEN
Added comment: Three individuals who each share a recurrent de novo germline variant in the MAX gene, resulting in a p.Arg60Gln substitution in the loop of the b-HLH-LZ domain.

Affected individuals have a complex disorder consisting primarily of macrocephaly, polydactyly, and delayed ophthalmic development. Other phenotypes reported include intellectual disability, perianal abscesses, pectus carinatum, hypospadias, renal agenesis, single umbilical artery, flattened thoracic vertebrae.

Functional analysis of the p.Arg60Gln variant shows a significant increase in CCND2 protein and a more efficient heterodimerization with c-Myc resulting in an increase in transcriptional activity of c-Myc.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5660 ZRSR2 Chris Ciotta gene: ZRSR2 was added
gene: ZRSR2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZRSR2 was set to X-LINKED: hemizygous mutation in males, biallelic mutations in females
Publications for gene: ZRSR2 were set to PMID: 38158857
Phenotypes for gene: ZRSR2 were set to Orofacialdigital syndrome MONDO:0015375, ZRSR2-related
Review for gene: ZRSR2 was set to GREEN
Added comment: Oral-facial-digital (OFD) syndrome with brain anomalies ranging from alobar holoprosencephaly to pituitary anomalies.
Six unrelated families with two truncating variants and functional studies:
- p.(Gly404GlufsTer23): detected in one family with 2x affected males
- p.(Arg403GlyfsTer24): 5 unrelated families, both de novo and inherited
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5660 BORCS8 Lauren Rogers changed review comment from: 3 unrelated families with five affected children with homozygous or compound heterozygous loss of function missense and PTC variants.

HEK293T cells show the missense variants are expressed at normal levels but exhibit reduced assembly with other BORC subunits and reduced ability to drive lysosome distribution. The BORCS8 PTC frameshift variant is expressed at lower levels and is completely incapable of assembling with other BORC subunits and promoting lysosome distribution. Zebrafish KO of the orthologous brocs8 causes decreased brain and eye size, neuromuscular anomalies and impaired locomotion, recapitulating some of the key traits of the human disease.
Sources: Literature; to: 3 unrelated families with five affected children with homozygous or compound heterozygous loss of function missense and PTC variants. 5/5 hypotonia, failure to thrive, global developmental delay, profound intellectual disability, muscle weakness and atrophy, dysmorphic features. 3/5 with microcephaly, 3/5 with seizures, 4/5 with spasticity, 3/5 with scoliosis, 4/4 with optic atrophy.

HEK293T cells show the missense variants are expressed at normal levels but exhibit reduced assembly with other BORC subunits and reduced ability to drive lysosome distribution. The BORCS8 PTC frameshift variant is expressed at lower levels and is completely incapable of assembling with other BORC subunits and promoting lysosome distribution. Zebrafish KO of the orthologous brocs8 causes decreased brain and eye size, neuromuscular anomalies and impaired locomotion, recapitulating some of the key traits of the human disease.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5659 GTPBP1 Lucy Spencer gene: GTPBP1 was added
gene: GTPBP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GTPBP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GTPBP1 were set to 38118446
Phenotypes for gene: GTPBP1 were set to Neurodevelopmental disorder (MONDO#0700092), GTPBP1-related
Review for gene: GTPBP1 was set to GREEN
Added comment: PMID: 38118446- Cohort of individuals with variants in GTPBP2 (which has been previously described) and GTPBP1 (new) who have an identical neurodevelopmental syndrome. 4 homozygous individuals from 3 consanguineous families. 2 families have different NMD-predicted nonsense variants and the third has a missense, all are absent from gnomad v4.

The shared cardinal features of GTPBP1 and 2 related disease are microcephaly, profound neurodevelopmental impairment, and distinctive craniofacial features. Epilepsy was present in 10 of 20 individuals but its not clear if those individuals had GTPBP1 or 2 variants.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5659 PUS3 Zornitza Stark Phenotypes for gene: PUS3 were changed from Mental retardation, autosomal recessive 55, MIM# 617051 to Neurodevelopmental disorder with microcephaly and gray sclerae, MIM# 617051
Intellectual disability syndromic and non-syndromic v0.5658 PUS3 Zornitza Stark edited their review of gene: PUS3: Changed phenotypes: Neurodevelopmental disorder with microcephaly and gray sclerae, MIM# 617051
Intellectual disability syndromic and non-syndromic v0.5652 GPT2 Zornitza Stark Phenotypes for gene: GPT2 were changed from Mental retardation, autosomal recessive 49, MIM#616281 to Neurodevelopmental disorder with microcephaly and spastic paraplegia, MIM# 616281
Intellectual disability syndromic and non-syndromic v0.5650 CASP2 Zornitza Stark Phenotypes for gene: CASP2 were changed from neurodevelopmental disorder MONDO:0700092, CASP2-related to Intellectual developmental disorder, autosomal recessive 80, with variant lissencephaly, MIM# 620653
Intellectual disability syndromic and non-syndromic v0.5649 CASP2 Zornitza Stark reviewed gene: CASP2: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Intellectual developmental disorder, autosomal recessive 80, with variant lissencephaly, MIM# 620653; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5633 SV2A Zornitza Stark Phenotypes for gene: SV2A were changed from Epilepsy, MONDO:0005027; microcephaly MONDO:0001149; intellectual disability MONDO:0001071 to Neurodevelopmental disorder, MONDO:0700092, SV2A-related
Intellectual disability syndromic and non-syndromic v0.5631 SV2A Karina Sandoval gene: SV2A was added
gene: SV2A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SV2A was set to BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal
Publications for gene: SV2A were set to PMID: 37985816
Phenotypes for gene: SV2A were set to Epilepsy, MONDO:0005027; microcephaly MONDO:0001149; intellectual disability MONDO:0001071
Review for gene: SV2A was set to AMBER
Added comment: Monoallelic variants cause epilepsy. Biallelic variant in this 5yo with p.Arg289Ter and another 5yo from another paper with homozygous p.Arg383Gln, reported to cause severe phenotype of drug-resistant epileptic encephalopathy with microcephaly, DD, movement disorder and growth retardation.
This paper references 5 other families with both AR & AD
Family #1 – p.Arg383Gln, AR, 2 affected in family, parents healthy carriers
Family #2 – p.Arg570Cys, AD, 2 affected, inherited from affected mother (in gnomAD v2 1 het, absent from gnomAD v3)
Family #3 – p.Gly660Arg, AD, de novo
Family #4 – p.Gly660Arg, AD, segregated in 11 family members
Family #5 (this study) – p.Arg289Ter, AR, parents and 2 sibs asymptomatic carriers
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5631 RAB1A Chris Ciotta gene: RAB1A was added
gene: RAB1A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RAB1A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RAB1A were set to PMID: 37924809
Phenotypes for gene: RAB1A were set to neurodevelopmental disorder MONDO:0700092, CASP2-related
Review for gene: RAB1A was set to AMBER
Added comment: 4 families and 5 individuals, 2/5 have speech delay and 4/5 have motor delay.
Anxiety in 3/5 and autism in 2/5. Microcephaly in only one individual, spastic paraplegia observed in 2 individuals from one family.
In 2 families variants were inherited from an affected parent.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5627 SEL1L Sarah Pantaleo gene: SEL1L was added
gene: SEL1L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SEL1L was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SEL1L were set to PMID: 37943610; PMID: 37943617
Phenotypes for gene: SEL1L were set to Neurodevelopmental disorder, MONDO:0700092, SEL1L-related
Penetrance for gene: SEL1L were set to Complete
Review for gene: SEL1L was set to GREEN
Added comment: Wang paper PMID: 37943610

SEL1L protein is involved in the SEL1L-HRD1 endoplasmic reticulum (ER)-associated degradation.

Report two biallelic missense variants in SEL1L in six children from three independent families presenting with developmental delay, intellectual disability, microcephaly, facial dysmorphisms, hypotonia and/or ataxia (termed ERAD-associated neurodevelopment disorder with onset in infancy (ENDI). The variants were hypomorphic and impaired ERAD function.

Identified by WES. Parents heterozygous and asymptomatic. P.(Gly585Asp) in Patient 1, p.(Met528Arg) in Patients 2 and 3 (siblings).

All variants cause substrate accumulation. The extent of substrate accumulation in knockin cells was modest compared to those in knockout cells, pointing to a hypomorphic nature.

They also had a variant in HRD1.



Weis paper PMID: 37943617

Third variant p.(Cys141Tyr), biallelic, causing premature death in five patients from a consanguineous family with early-onset neurodevelopmental disorders and agammaglobulinaemia due to severe SEL1L-HRD1 ERAD dysfunction.

This variant appears to have a more severe outcome, exhibiting B cell depletion and agammaglobulinaemia, causing the most severe dysfunction among all of the variants described by this group so far. They postulate that functionality of SEL1L-HRD1 ERAD is inversely correlated with disease severity in humans.

Their symptoms were dev delay, neurological disorder and agammaglobulinaemia in childhood. Along with severe axial hypotonia, short stature and microcephaly.

“Not a complete loss-of-function variant”.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5621 TRAPPC4 Zornitza Stark Phenotypes for gene: TRAPPC4 were changed from intellectual disability; epilepsy; spasticity; microcephaly to Neurodevelopmental disorder with epilepsy, spasticity, and brain atrophy, MIM# 618741
Intellectual disability syndromic and non-syndromic v0.5606 VCP Manny Jacobs gene: VCP was added
gene: VCP was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: VCP was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: VCP were set to PMID: 37883978
Phenotypes for gene: VCP were set to Neurodevelopmental disorder (MONDO: 0700092)
Review for gene: VCP was set to GREEN
Added comment: 13 unrelated individuals with childhood onset ID/DD disorder including macrocephaly, hypotonia and dysmorphic features. Non-specific / mild MRI findings.
12 de novo - 1 inherited
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5602 SGSM3 Dean Phelan gene: SGSM3 was added
gene: SGSM3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SGSM3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SGSM3 were set to PMID: 37833060
Phenotypes for gene: SGSM3 were set to Neurodevelopmental disorder (MONDO:0700092), SGSM3-related
Review for gene: SGSM3 was set to GREEN
Added comment: PMID: 37833060
- 13 patients from 8 families of Ashkenazi Jewish origin all had the same homozygous frameshift variant (c.981dup). Predicted to cause NMD. The variant co-segregated with disease in all available family members. The affected individuals displayed mild global developmental delay and mild to moderate intellectual disability. Additional prevalent phenotypes observed included hypotonia, behavioural challenges and short stature. Considered a founder variant (1 in 52 Ashkenazi Jews carry the variant). Also present in other populations but no homozygotes in gnomAD.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5599 CASP2 Ain Roesley gene: CASP2 was added
gene: CASP2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CASP2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CASP2 were set to 37880421
Phenotypes for gene: CASP2 were set to neurodevelopmental disorder MONDO:0700092, CASP2-related
Penetrance for gene: CASP2 were set to Complete
Review for gene: CASP2 was set to GREEN
gene: CASP2 was marked as current diagnostic
Added comment: 7 patients from 5 families
4 families hom for PTCs, 1 family Chet for splice+PTC
RNA studies done for the splice to indicate usage of 2 cryptic splice donor sites

5/5 have ID/dev delay
1/5 has seizures
2/5 hypotonia
3/5 lissencephaly (pachygyria and cortical thickening)
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5578 KCNH5 Zornitza Stark Phenotypes for gene: KCNH5 were changed from Neurodevelopmental disorder MONDO#0700092, KCNH5-related to Developmental and epileptic encephalopathy 112, MIM# 620537
Intellectual disability syndromic and non-syndromic v0.5576 KCNH5 Zornitza Stark reviewed gene: KCNH5: Rating: GREEN; Mode of pathogenicity: None; Publications: 36307226; Phenotypes: Developmental and epileptic encephalopathy 112, MIM# 620537; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5549 SMARCA4 Claire Fryer-Smith changed review comment from: Coffin-Siris syndrome is a congenital malformation syndrome characterized by developmental delay, intellectual disability, coarse facial features, feeding difficulties, and hypoplastic or absent fifth fingernails and fifth distal phalanges.

Missense and an in-frame deletion in SCARCA4 have been observed across 15 CSS patients in the literature (22426308, 23637025, 23929686), suggesting a dominant negative GoF effect.

LoF variants in SMARCA4 result in Rhabdoid tumor predisposition syndrome, which does not exhibit ID.; to: Coffin-Siris syndrome is a congenital malformation syndrome characterized by developmental delay, intellectual disability, coarse facial features, feeding difficulties, and hypoplastic or absent fifth fingernails and fifth distal phalanges.

Missense and an in-frame deletion in SMARCA4 have been observed across 15 CSS patients in the literature (22426308, 23637025, 23929686), suggesting a dominant negative GoF effect.

LoF variants in SMARCA4 result in Rhabdoid tumor predisposition syndrome, which does not exhibit ID.
Intellectual disability syndromic and non-syndromic v0.5549 STXBP1 Zornitza Stark Phenotypes for gene: STXBP1 were changed from to developmental and epileptic encephalopathy, 4 MONDO:0012812
Intellectual disability syndromic and non-syndromic v0.5528 TBC1D24 Zornitza Stark Phenotypes for gene: TBC1D24 were changed from to Developmental and epileptic encephalopathy 16, MIM# 615338; DOORS syndrome, MIM# 220500
Intellectual disability syndromic and non-syndromic v0.5524 STXBP1 Kaitlyn Dianna Weldon reviewed gene: STXBP1: Rating: GREEN; Mode of pathogenicity: None; Publications: 27905812; Phenotypes: developmental and epileptic encephalopathy, 4 MONDO:0012812; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5519 TANGO2 Zornitza Stark Phenotypes for gene: TANGO2 were changed from to Metabolic encephalomyopathic crises, recurrent, with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration, MIM# 616878; metabolic encephalomyopathic crises, recurrent, with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration MONDO:0014812
Intellectual disability syndromic and non-syndromic v0.5514 MYCN Naomi Baker commented on gene: MYCN: Three individuals now reported with gain-of-function missense variants (identical variant in two individuals). Clinical presentation includes megalencephaly, hypoplastic corpus callosum, postaxial polydactyly, intellectual disability and motor delay. Knock-in mouse model showed morphological manifestations in multiple tissues including digits, female reproductive system and kidney.
Intellectual disability syndromic and non-syndromic v0.5512 MAST4 Ain Roesley gene: MAST4 was added
gene: MAST4 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MAST4 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MAST4 were set to 36910266; 33057194
Phenotypes for gene: MAST4 were set to neurodevelopmental disorder MONDO:0700092, MAST4-related
Penetrance for gene: MAST4 were set to Complete
Review for gene: MAST4 was set to GREEN
gene: MAST4 was marked as current diagnostic
Added comment: PMID: 36910266 - 4 families with 4 affecteds, all de novo missense

2x borderline microcephaly (-2SD)
2x gross motor delay
2x dysmorphism
4x ID + seizures
3x abnormal brain MRI findings

PMID: 33057194 - 5x de novos, 4x missense + 1x PTC
Cohort of individuals with severe developmental disorder
individual phenotypic information not provided


Recurrent variants are Thr1471Ile (3x) and Ser1181Phe)
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5509 COG3 Daniel Flanagan gene: COG3 was added
gene: COG3 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: COG3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: COG3 were set to PMID: 37711075
Phenotypes for gene: COG3 were set to Neurodevelopmental disorder (MONDO#0700092), COG3-related
Review for gene: COG3 was set to AMBER
Added comment: Two COG3 homozygous missense variants in four individuals from two unrelated consanguineous families. Clinical phenotypes of affected individuals include global developmental delay, severe intellectual disability, microcephaly, epilepsy, facial dysmorphism, and variable neurological findings.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.5508 TANGO2 Kaitlyn Dianna Weldon reviewed gene: TANGO2: Rating: GREEN; Mode of pathogenicity: None; Publications: 29369572; Phenotypes: obsolete metabolic encephalomyopathic crises, recurrent, with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration MONDO:0014812; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5502 CSDE1 Zornitza Stark Phenotypes for gene: CSDE1 were changed from Autism; intellectual disability; seizures; macrocephaly to Neurodevelopmental disorder, MONDO:0700092, CSDE1-related
Intellectual disability syndromic and non-syndromic v0.5474 AGMO Zornitza Stark Phenotypes for gene: AGMO were changed from microcephaly; intellectual disability; epilepsy to Neurodevelopmental disorder, MONDO:0700092, AGMO-related
Intellectual disability syndromic and non-syndromic v0.5463 PTEN Zornitza Stark Phenotypes for gene: PTEN were changed from to Cowden syndrome 1 MIM#158350; Macrocephaly/autism syndrome MIM#605309
Intellectual disability syndromic and non-syndromic v0.5455 UBA5 Zornitza Stark Phenotypes for gene: UBA5 were changed from to Epileptic encephalopathy, early infantile, 44 (MIM#617132)
Intellectual disability syndromic and non-syndromic v0.5426 WWOX Zornitza Stark Phenotypes for gene: WWOX were changed from to developmental and epileptic encephalopathy, 28 MONDO:0014533; autosomal recessive spinocerebellar ataxia 12 MONDO:0013687
Intellectual disability syndromic and non-syndromic v0.5423 XRCC4 Zornitza Stark Phenotypes for gene: XRCC4 were changed from to Short stature, microcephaly, and endocrine dysfunction MIM#616541, MONDO:0014686
Intellectual disability syndromic and non-syndromic v0.5411 ZIC2 Zornitza Stark Phenotypes for gene: ZIC2 were changed from to Holoprosencephaly 5 MONDO:0012322
Intellectual disability syndromic and non-syndromic v0.5399 PTEN Claire Fryer-Smith reviewed gene: PTEN: Rating: GREEN; Mode of pathogenicity: None; Publications: 21194675, 1859181, 23470840; Phenotypes: Cowden syndrome 1 MIM#158350, Lhermitte-Duclos disease MIM#158350, Macrocephaly/autism syndrome MIM#605309, Prostate cancer, somatic MIM#176807; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5399 TUBG1 Kaitlyn Dianna Weldon reviewed gene: TUBG1: Rating: GREEN; Mode of pathogenicity: None; Publications: 29706637, 23603762; Phenotypes: complex cortical dysplasia with other brain malformations 4 MONDO:0014171, lissencephaly spectrum disorders MONDO:0018838; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5399 WWOX Kaitlyn Dianna Weldon reviewed gene: WWOX: Rating: GREEN; Mode of pathogenicity: None; Publications: 25411445, 24369382; Phenotypes: developmental and epileptic encephalopathy, 28 MONDO:0014533, autosomal recessive spinocerebellar ataxia 12 MONDO:0013687; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5399 XRCC4 Claire Fryer-Smith reviewed gene: XRCC4: Rating: GREEN; Mode of pathogenicity: None; Publications: 25872942, 25839420, 18695064; Phenotypes: Short stature, microcephaly, and endocrine dysfunction MIM#616541; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5399 XRCC4 Kaitlyn Dianna Weldon reviewed gene: XRCC4: Rating: GREEN; Mode of pathogenicity: None; Publications: 25728776; Phenotypes: short stature, microcephaly, and endocrine dysfunction MONDO:0014686; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5399 ZIC2 Kaitlyn Dianna Weldon reviewed gene: ZIC2: Rating: GREEN; Mode of pathogenicity: None; Publications: 21940735; Phenotypes: holoprosencephaly 5 MONDO:0012322; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5390 RAB5C Rylee Peters changed review comment from: 12 individuals with nine different heterozygous de novo variants in RAB5C.
9 with missense, 1 inframe duplication and 2 stop-gains (clinically more severe).
All has mild-severe ID, 4/12 have epilepsy, 6/12 have macrocephaly (more than 3 SD).
Sources: Literature; to: 12 individuals with nine different heterozygous de novo variants in RAB5C.
9 with missense, 1 inframe duplication and 2 stop-gains (clinically more severe).
All have mild to severe ID, 4/12 have epilepsy, 6/12 have macrocephaly (more than 3 SD).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5387 RAB5C Rylee Peters gene: RAB5C was added
gene: RAB5C was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RAB5C was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RAB5C were set to PMID: 37552066
Phenotypes for gene: RAB5C were set to Neurodevelopmental disorder MONDO:0700092, RAB5C-related
Penetrance for gene: RAB5C were set to Complete
Review for gene: RAB5C was set to GREEN
gene: RAB5C was marked as current diagnostic
Added comment: 12 individuals with nine different heterozygous de novo variants in RAB5C.
9 with missense, 1 inframe duplication and 2 stop-gains (clinically more severe).
All has mild-severe ID, 4/12 have epilepsy, 6/12 have macrocephaly (more than 3 SD).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5387 AXIN1 Elena Savva gene: AXIN1 was added
gene: AXIN1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: AXIN1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: AXIN1 were set to PMID: 37582359
Phenotypes for gene: AXIN1 were set to Syndromic disease, (MONDO:0002254), AXIN1-related
Review for gene: AXIN1 was set to GREEN
Added comment: PMID: 37582359
- four families (7 individuals) with three homozygous truncating variants.
- all variant shown to result in reduced protein, though 1/3 would be NMD predicted
- Probands had macrocephaly (4/6), GDD (3/7), hip dysplasia (5/6), cardiac anomalies eg. VSD/ASD (3/7), cranial hyperostosis and vertebral endplate sclerosis
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5383 SOX11 Zornitza Stark Phenotypes for gene: SOX11 were changed from Coffin-Siris syndrome 9, OMIM # 615866 to Intellectual developmental disorder with microcephaly and with or without ocular malformations or hypogonadotropic hypogonadism, MIM# 615866
Intellectual disability syndromic and non-syndromic v0.5381 SOX11 Zornitza Stark reviewed gene: SOX11: Rating: GREEN; Mode of pathogenicity: None; Publications: 29459093, 24886874, 33086258, 33785884, 35642566, 35341651; Phenotypes: Intellectual developmental disorder with microcephaly and with or without ocular malformations or hypogonadotropic hypogonadism, MIM# 615866; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.5365 ARX Zornitza Stark Phenotypes for gene: ARX were changed from to Lissencephaly, X-linked 2, MIM# 300215
Intellectual disability syndromic and non-syndromic v0.5363 ARX Zornitza Stark reviewed gene: ARX: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Lissencephaly, X-linked 2, MIM# 300215; Mode of inheritance: X-LINKED: hemizygous mutation in males, biallelic mutations in females
Intellectual disability syndromic and non-syndromic v0.5363 ARV1 Zornitza Stark Phenotypes for gene: ARV1 were changed from to Developmental and epileptic encephalopathy 38, MIM# 617020
Intellectual disability syndromic and non-syndromic v0.5360 ARV1 Zornitza Stark reviewed gene: ARV1: Rating: GREEN; Mode of pathogenicity: None; Publications: 35227294, 27270415, 25558065; Phenotypes: Developmental and epileptic encephalopathy 38, MIM# 617020; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5357 UBAP2L Zornitza Stark Phenotypes for gene: UBAP2L were changed from Neurodevelopmental disorder, MONDO:0700092, UBAP2L-related; Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system to Neurodevelopmental disorder with impaired language, behavioral abnormalities, and dysmorphic facies, MIM# 620494; Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system
Intellectual disability syndromic and non-syndromic v0.5353 AMT Zornitza Stark Phenotypes for gene: AMT were changed from to Glycine encephalopathy MIM#605899
Intellectual disability syndromic and non-syndromic v0.5351 AMT Zornitza Stark reviewed gene: AMT: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Glycine encephalopathy MIM#605899; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5336 ATP6V0C Zornitza Stark Phenotypes for gene: ATP6V0C were changed from Epilepsy; Intellectual Disability; microcephaly to Epilepsy, early-onset, with or without developmental delay, MIM#620465; Epilepsy; Intellectual Disability; microcephaly
Intellectual disability syndromic and non-syndromic v0.5323 AQP4 Zornitza Stark Phenotypes for gene: AQP4 were changed from ?Megalencephalic leukoencephalopathy with subcortical cysts 4, remitting MIM#620448 to Megalencephalic leukoencephalopathy with subcortical cysts 4, remitting MIM#620448
Intellectual disability syndromic and non-syndromic v0.5317 AQP4 Lucy Spencer gene: AQP4 was added
gene: AQP4 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: AQP4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: AQP4 were set to 37143309
Phenotypes for gene: AQP4 were set to ?Megalencephalic leukoencephalopathy with subcortical cysts 4, remitting MIM#620448
Review for gene: AQP4 was set to AMBER
Added comment: PMID: 37143309
Cohort patients with an MRI based diagnosis of megalencephalic leukoencephalopathy with subcortical cysts (MLC). Missense variant in AQP4 seen homozygous in 2 siblings and het in the parents. Patients had macrocephaly, developmental delay, hypotonia, epilepsy, and cognitive deficit.

Western blots on generated MDCK cell lines showed no detectable expression of AQP4 protein from the cells with the patients variant. Immunofluorescence also showed no membrane expression. Overexpression studies in HEK293T cells showed WT was seen as mainly monomers or dimers where as variant protein formed large aggregates- likely due to the saturation of protein degradation pathways because of the overexpression.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5313 GPRC5B Lucy Spencer gene: GPRC5B was added
gene: GPRC5B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GPRC5B was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: GPRC5B were set to PMID: 37143309
Phenotypes for gene: GPRC5B were set to Megalencephalic leukoencephalopathy with subcortical cysts 3 MIM#620447
Review for gene: GPRC5B was set to GREEN
Added comment: PMID: 37143309
Cohort of 5 patients with an MRI based diagnosis of megalencephalic leukoencephalopathy with subcortical cysts (MLC). 3 unrelated patients had variants in GPRC5B, 2 have the same inframe dup Ile175dup and the third has an in frame dup of Ala177. All 3 were de novo and unaffected siblings did not have the variants. All patients have macrocephaly, delayed motor development, spasticity, ataxia and dystonia, seizures, all had varying degrees of cognitive deficits. MRI showed MLC, abnormal and swollen cerebral white matter.

Patient cell lines showed reduced regulatory volume decrease, and western blot showed a strong increase in GRPC5B levels in patient lymphoblasts. Together, these findings indicate disturbed volume regulation in lymphoblasts from patients with GPRC5B variants, potentially due to increased GPRC5B levels. Transfected cells caused increased volume-regulated anion channel activity.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5313 SLC4A10 Krithika Murali gene: SLC4A10 was added
gene: SLC4A10 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SLC4A10 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLC4A10 were set to PMID: 37459438
Phenotypes for gene: SLC4A10 were set to Neurodevelopmental disorderMONDO:0700092, SLC4A10-related
Review for gene: SLC4A10 was set to GREEN
Added comment: PMID: 37459438 Fasham et al 2023 (Brain) report 10 affected individuals from 5 unrelated families with biallelic LoF variants in this gene with a novel neurodevelopmental disorder.

Phenotypic features include hypotonia in infancy, delayed psychomotor development, typically severe ID, progressive postnatal microcephaly, ASD traits, corpus callosal abnormalities and 'slit-like' lateral ventricles. These phenotypic features were recapitulated in knockout mice with additional supportive functional studies.

Isolated seizures was reported in 2/10 cases.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5312 SLC4A10 Krithika Murali gene: SLC4A10 was added
gene: SLC4A10 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SLC4A10 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLC4A10 were set to PMID: 37459438
Phenotypes for gene: SLC4A10 were set to Neurodevelopmental disorderMONDO:0700092, SLC4A10-related
Review for gene: SLC4A10 was set to GREEN
Added comment: PMID: 37459438 Fasham et al 2023 (Brain) report 10 affected individuals from 5 unrelated families with biallelic LoF variants in this gene with a novel neurodevelopmental disorder.

Phenotypic features include hypotonia in infancy, delayed psychomotor development, typically severe ID, progressive postnatal microcephaly, ASD traits, corpus callosal abnormalities and 'slit-like' lateral ventricles. These phenotypic features were recapitulated in knockout mice with additional supportive functional studies.

Isolated seizures was reported in 2/10 cases.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5308 TMEM63B Zornitza Stark gene: TMEM63B was added
gene: TMEM63B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TMEM63B was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: TMEM63B were set to 37421948
Phenotypes for gene: TMEM63B were set to developmental and epileptic encephalopathy, MONDO:0100062, TMEM63B-related
Review for gene: TMEM63B was set to GREEN
Added comment: 17 unrelated individuals with severe early-onset developmental and epileptic encephalopathy (DEE), intellectual disability, and severe motor and cortical visual impairment were identified with ten distinct heterozygous variants inTMEM63B. The variants occurred de novo in 16/17 individuals for whom parental DNA was available and either missense or in-frame. All individuals had global developmental delay, with moderate-to-profound intellectual disability and severe motor impairment. All individuals had early-onset drug-resistant epilepsy, whose onset ranged from birth to 3 years but occurred within the first year in 14/17 (82%) and in the first month of life in 6/17 (35%).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5301 PIP5K1C Zornitza Stark Phenotypes for gene: PIP5K1C were changed from Neurodevelopmental disorder and microcephaly to Neurodevelopmental disorder and microcephaly, MONDO:0700092, PIP5K1C-related
Intellectual disability syndromic and non-syndromic v0.5298 TEFM Zornitza Stark gene: TEFM was added
gene: TEFM was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TEFM was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TEFM were set to 36823193
Phenotypes for gene: TEFM were set to Combined oxidative phosphorylation deficiency 58, MIM# 620451
Review for gene: TEFM was set to GREEN
Added comment: Seven individuals from 5 families reported. Presentation predominantly with encephalopathy, seizures and ID, in addition to lactic acidosis.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5297 CYHR1 Zornitza Stark Phenotypes for gene: CYHR1 were changed from Neurodevelopmental disorder and microcephaly to Neurodevelopmental disorder and microcephaly, MONDO:0700092, CYHR1-related
Intellectual disability syndromic and non-syndromic v0.5286 TTI1 Zornitza Stark Phenotypes for gene: TTI1 were changed from Neurodevelopmental disorder, MONDO:0700092, TTI1-related to Neurodevelopmental disorder with microcephaly and movement abnormalities, MIM# 620445
Intellectual disability syndromic and non-syndromic v0.5278 PIP5K1C Chirag Patel gene: PIP5K1C was added
gene: PIP5K1C was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: PIP5K1C was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: PIP5K1C were set to Neurodevelopmental disorder and microcephaly
Review for gene: PIP5K1C was set to GREEN
gene: PIP5K1C was marked as current diagnostic
Added comment: ESHG 2023:
9 unrelated patients with de novo missense variants in PIP5K1C (3 x recurrent variants).
Presentation with DD/ID (mod-profound), microcephaly, seizures, visual impairment, and dysmorphism.

PIP5K1C is one of the phosphoinositolides, which control membrane composition of organelles and varying cellular processes. Patient fibroblasts showed increased PI(4,5)P2 levels, altered PI(4,5)P2 composition of early endosomes, and impaired endocytosis trafficking. Drosophila models showed microcephaly and ocular phenotype.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.5273 DCAF15 Chirag Patel gene: DCAF15 was added
gene: DCAF15 was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: DCAF15 was set to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: DCAF15 were set to Cornelia de Lange syndrome
Review for gene: DCAF15 was set to AMBER
Added comment: ESHG 2023:
3 unrelated cases with CdLS (1 x TOP with MCA, 1 x death @20mths, 1 x living child)
Features suggestive of CdLS - DD, microcephaly, CHD, dysmorphism, visual/hearing impairment.

WES identified recurrent de novo variant (p.Ser470Phe) in DCAF15 gene. This mediates ubiquitination and degradation of target proteins, and interacts with cohesin complex members (SMC1/SMC3).

Protein analysis from individuals showed increased accumulation of ubiquitination-modified proteins and SM3 (GOF mechanism). EpiSign analysis showed same DNA methylation pattern as other CdLS cases/genes. Zebrafish model showed reduced body length, reduced head size, reduced oligodendrocytes, heart defect, aberrant motor neurons, and abnormal response to visual/auditory stimuli.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.5271 CYHR1 Chirag Patel gene: CYHR1 was added
gene: CYHR1 was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: CYHR1 was set to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: CYHR1 were set to Neurodevelopmental disorder and microcephaly
Review for gene: CYHR1 was set to AMBER
gene: CYHR1 was marked as current diagnostic
Added comment: ESHG 2023:
5 individuals from 3 families with biallelic LOF variants in CYHR1 (aka ZTRAF1). Presentation with microcephaly, hypotonia, DD, and ID. Expression studies showed mislocalisation of CYHR1. Mutant fibroblasts showed increased lysosomal markers and upregulated lysosomal proteins, leading to impaired autophagy. Zebrafish KO however did not show a phenotype.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.5258 HCN2 Elena Savva gene: HCN2 was added
gene: HCN2 was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: HCN2 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Phenotypes for gene: HCN2 were set to Febrile seizures, familial, 2 MIM#602477; Generalized epilepsy with febrile seizures plus, type 11 MIM#602477; {Epilepsy, idiopathic generalized, susceptibility to, 17} MIM#602477; Neurodevelopmental disorder (MONDO#0700092), HCN2-related
Review for gene: HCN2 was set to AMBER
Added comment: ICG 2023 conference
- cohort of 20 individuals where >80% had a form of intellectual disability (half were severe) and/or seizures. Some had isolated intellectual disability, especially those with a recurring de novo p.E478del.
- Patients were both mono- and biallelic.
- Monoallelic individuals had de novo missense and an inframe deletion. Biallelic individuals had a mix of missense and PTC
Sources: Other
Intellectual disability syndromic and non-syndromic v0.5251 ERI1 Elena Savva gene: ERI1 was added
gene: ERI1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ERI1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ERI1 were set to 37352860
Phenotypes for gene: ERI1 were set to Intellectual disability (MONDO#0001071), ERI1-related
Review for gene: ERI1 was set to GREEN
Added comment: PMID: 37352860 - 8 individuals from 7 unrelated families
- Patients with biallelic missense show a MORE severe spondyloepimetaphyseal dysplasia, syndactyly, brachydactyly/clinodactyly/camptodactyly
- Patients with biallelic null/whole gene deletion had mild ID and digit anomalies including brachydactyly/clinodactyly/camptodactyly
- Patient chet for a missense and PTC variant has a blended phenotype with short stature, syndactyly, brachydactyly/clinodactyly/camptodactyly, mild ID and failure to thrive

- Missense variants were functionally shown to not be able to rescue 5.8S rRNA processing in KO HeLa cells
- K/O mice had neonatal lethality with growth defects, brachydactyly. Skeletal-specific K/O had mild platyspondyly, had more in keeping with patients with null variants than missense

More severe phenotype hypothesised due to "exonuclease-dead proteins may compete for the target RNA molecules with other exonucleases that have functional redundancy
with ERI1, staying bound to those RNA molecules"
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5250 DRG1 Dean Phelan gene: DRG1 was added
gene: DRG1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: DRG1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DRG1 were set to PMID: 37179472
Phenotypes for gene: DRG1 were set to Neurodevelopmental disorder (MONDO:0700092), DRG1-related
Review for gene: DRG1 was set to GREEN
Added comment: PMID: 37179472
- Biallelic variants were identified in four affected individuals from three distinct families with neurodevelopmental disorder with global developmental delay, primary microcephaly, short stature and craniofacial anomalies. Functional studies show the variants result in a loss of function.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5247 GCSH Zornitza Stark Phenotypes for gene: GCSH were changed from Glycine encephalopathy MIM#605899; neurodevelopmental disorder MONDO#0700092, GCHS-related to Multiple mitochondrial dysfunctions syndrome 7, MIM# 620423
Intellectual disability syndromic and non-syndromic v0.5230 MCM6 Suliman Khan gene: MCM6 was added
gene: MCM6 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MCM6 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MCM6 were set to PMID: 37198333
Phenotypes for gene: MCM6 were set to Neurodevelopmental disorder, MONDO:0700092, MCM6-related
Review for gene: MCM6 was set to GREEN
Added comment: PMID: 37198333 reported 5 unrelated families with de novo variants in MCM6 gene. Two patients with the same missense variant p.(Cys158Tyr) in zinc finger domain presented with intra-uterine growth retardation, short stature, congenital microcephaly, endocrine features, developmental delay and urogenital anomalies.

In other three unrelated individuals different de novo missense variants were identified in the oligo nucleotide binding (OB)-fold domain. These patients had variable neurodevelopmental features including autism spectrum disorder, developmental delay, and epilepsy.

The clinical features and functional defects related to the zinc binding residue resembled those observed in syndromes related to other MCM components and DNA replication factors (Meier–Gorlin syndrome and Seckel syndrome), while de novo OB-fold domain missense variants were associated with more variable neurodevelopmental phenotypes (PMID: 37198333).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5214 GATAD2A Bryony Thompson gene: GATAD2A was added
gene: GATAD2A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GATAD2A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: GATAD2A were set to https://doi.org/10.1016/j.xhgg.2023.100198; 17565372
Phenotypes for gene: GATAD2A were set to Neurodevelopmental disorder, MONDO:0700092, GATAD2A-related
Review for gene: GATAD2A was set to GREEN
Added comment: https://doi.org/10.1016/j.xhgg.2023.100198 - Five unrelated individuals with a neurodevelopmental disorder identified with 3 missense & 2 LoF (4 de novo & 1 unknown inheritance). The shared clinical features with variable expressivity include global developmental delay (4/4), craniofacial dysmorphism (3/5), structural brain defects (2/3), musculoskeletal anomalies (3/5), vision/hearing defects (2/3), gastrointestinal/renal defects (2/3). Loss of function is the expected mechanism of disease. In vitro assays of one of the missense variants (p.Cys420Tyr) demonstrates disruption of GATAD2A integration with CHD3, CHD4, and CHD5
PMID: 17565372 - null mouse model is embryonic lethal.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5210 DNM1 Zornitza Stark Phenotypes for gene: DNM1 were changed from Developmental and epileptic encephalopathy 31, OMIM:616346 to Developmental and epileptic encephalopathy 31A, autosomal dominant, MIM# 616346; Developmental and epileptic encephalopathy 31B, autosomal recessive, MIM# 620352
Intellectual disability syndromic and non-syndromic v0.5209 DNM1 Zornitza Stark edited their review of gene: DNM1: Changed phenotypes: Developmental and epileptic encephalopathy 31A, autosomal dominant, MIM# 616346, Developmental and epileptic encephalopathy 31B, autosomal recessive, MIM# 620352
Intellectual disability syndromic and non-syndromic v0.5206 WARS Zornitza Stark Phenotypes for gene: WARS were changed from Neurodevelopmental disorder (MONDO:0700092), WARS-related to Neurodevelopmental disorder withmicrocephaly and speech delay, with or without brain abnormalities,MIM# 620317
Intellectual disability syndromic and non-syndromic v0.5205 WARS Zornitza Stark reviewed gene: WARS: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder withmicrocephaly and speech delay, with or without brain abnormalities,MIM# 620317; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5202 CAMSAP1 Zornitza Stark Phenotypes for gene: CAMSAP1 were changed from lissencephaly spectrum disorders (MONDO:0018838), CAMSAP1-related to Cortical dysplasia, complex, with other brain malformations 12, MIM# 620316
Intellectual disability syndromic and non-syndromic v0.5198 CRIPT Karina Sandoval gene: CRIPT was added
gene: CRIPT was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CRIPT was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CRIPT were set to PMID: 37013901
Phenotypes for gene: CRIPT were set to Short stature with microcephaly and distinctive facies (MIM#615789) : Rothmund-Thomson syndrome MONDO:0010002
Review for gene: CRIPT was set to GREEN
Added comment: Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5182 RBSN Achchuthan Shanmugasundram gene: RBSN was added
gene: RBSN was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RBSN was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: RBSN were set to 25233840; 29784638; 35652444
Phenotypes for gene: RBSN were set to intellectual disability, MONDO:0001071
Review for gene: RBSN was set to GREEN
Added comment: This gene should be rated GREEN as bi-allelic variants in RBSN has been associated with a phenotype encompassing developmental delay and intellectual disability from four unrelated families.

PMID:25233840 reported a 6.5 year old female patient with a homozygous missense variant c.1273G > A (p.Gly425Arg) and her clinical presentation included intractable seizures, developmental delay, microcephaly, dysostosis, osteopenia, craniofacial dysmorphism, macrocytosis and megaloblastoid erythropoiesis.

PMID:29784638 reported three siblings with homozygous variant c.289G>C (p.Gly97Arg) in RBSN. The proband presented global developmental delay, had complete 46,XY male-to-female sex reversal and died at age 20 months after multiple infections. The other 2 affected siblings underwent unrelated-donor bone marrow or stem cell transplantation at 8 and 6.5 months of age, respectively. Both have severe intellectual disability and are nonambulatory and nonverbal.

PMID:35652444 reported two unrelated families (three siblings from a family of Iranian descent identified with homozygous variant c.547G>A (p.Gly183Arg) and four members from a family of indigenous Cree descent identified with homozygous variant c.538C>G (p.Arg180Gly)) with overlapping phenotypes including developmental delay, intellectual disability, distal motor axonal neuropathy and facial dysmorphism.

This gene has not yet been associated with any phenotypes either in OMIM or in Gene2Phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5182 CTR9 Achchuthan Shanmugasundram changed review comment from: PMID:35717577 reported two additional unrelated cases with non-synonymous heterozygous CTR9 variants (p.Glu15Asp and p.Pro25Arg) and they presented with macrocephaly, motor delay, and intellectual disability. In addition, functional studies in also showed that knockout/ over-expression of CTR9 variants caused motor defects and enlargement of telencephalon (homologous to the mammalian cerebrum).; to: PMID:35717577 reported two additional unrelated cases with non-synonymous heterozygous CTR9 variants (p.Glu15Asp and p.Pro25Arg) and they presented with macrocephaly, motor delay, and intellectual disability. In addition, functional studies in zebrafish also showed that knockout/ over-expression of CTR9 variants caused motor defects and enlargement of telencephalon (homologous to the mammalian cerebrum).
Intellectual disability syndromic and non-syndromic v0.5177 ROBO1 Achchuthan Shanmugasundram gene: ROBO1 was added
gene: ROBO1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ROBO1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ROBO1 were set to 28286008; 30692597; 35227688; 35348658
Phenotypes for gene: ROBO1 were set to intellectual disability, MONDO:0001071
Review for gene: ROBO1 was set to GREEN
Added comment: Comment on gene classification: This gene should be rated green as this gene has been associated with intellectual disability from six unrelated cases. However, the MOI should be set as "BIALLELIC, autosomal or pseudoautosomal" as five of these cases were reported with biallelic variants and only one case was reported with monoallelic variant.

PMID:28286008 reported a boy with compound heterozygous variants that was presented with developmental delay in 13 months and had severe intellectual disability and hyperactivity at nine years of age. He was nonverbal and wheelchair dependent because of spastic diplegia and ataxia.

PMID:30692597 reported a five year old boy identified with a homozygous ROBO1 variant who had combined pituitary hormone deficiency, psychomotor developmental delay, severe intellectual disability, sensorineural hearing loss, strabismus and characteristic facial features.

PMID:35227688 reported eight patients including the boy reported in PMID:30692597. Of the other seven patients, three were presented with intellectual disability. Of these three patients, two harboured compound heterozygous and one harboured homozygous variants.

PMID:35348658 reported a patient identified with monoallelic de novo variant (p.D422G) who presented with early-onset epileptic encephalopathy and had severe developmental delay.

This gene has not yet been associated with any phenotypes in OMIM or Gene2Phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5168 ATP9A Zornitza Stark Phenotypes for gene: ATP9A were changed from Neurodevelopmental delay; Postnatal microcephaly; Failure to thrive; Gastrointestinal symptoms to Neurodevelopmental disorder with poor growth and behavioural abnormalities, MIM# 620242
Intellectual disability syndromic and non-syndromic v0.5158 CCDC84 Lucy Spencer gene: CCDC84 was added
gene: CCDC84 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CCDC84 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CCDC84 were set to 34009673
Phenotypes for gene: CCDC84 were set to Mosaic variegated aneuploidy syndrome 4 (MIM#620153)
Review for gene: CCDC84 was set to AMBER
Added comment: PMID: 34009673- patients with constitutional mosaic aneuploidy were found to have biallelic mutations in CENATAC(CCDC84). 2 adult siblings with mosaic aneuploidies, microcephaly, dev delay, and maculopathy. Both chet for a missense and a splice site deletion- but the paper days these both result in the creation of a novel splice site that leads to frameshifts and loss of the c-terminal 64 amino acids.

Gene is shown to be part of a spliceosome. CENATAC depletion or expression of disease mutants resulted in retention of introns in ~100 genes enriched for nucleocytoplasmic transport and cell cycle regulation, and caused chromosome segregation errors.

Functional analysis in CENATAC-depleted HeLa cells demonstrated chromosome congression defects and subsequent mitotic arrest, which could be fully rescued by wildtype but not mutant CENATAC. Expression of the MVA-associated mutants exacerbated the phenotype, suggesting that the mutant proteins dominantly repress the function of any residual wildtype protein.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5156 FGF13 Zornitza Stark Phenotypes for gene: FGF13 were changed from Developmental and epileptic encephalopathy 90, MIM# 301058; Intellectual disability; epilepsy to Developmental and epileptic encephalopathy 90, MIM# 301058; Intellectual developmental disorder, X-linked 110, MIM# 301095
Intellectual disability syndromic and non-syndromic v0.5154 FGF13 Zornitza Stark edited their review of gene: FGF13: Added comment: PMID 34184986: 3 individuals reported with moderate to severe ID and maternally inherited 5' variant c.-32C-G; Changed publications: 33245860, 34184986; Changed phenotypes: Developmental and epileptic encephalopathy 90, MIM# 301058, Intellectual developmental disorder, X-linked 110, MIM# 301095
Intellectual disability syndromic and non-syndromic v0.5154 ZNF668 Zornitza Stark Phenotypes for gene: ZNF668 were changed from DNA damage repair defect; microcephaly; growth deficiency; severe global developmental delay; brain malformation; facial dysmorphism to Neurodevelopmental disorder with poor growth, large ears, and dysmorphic facies, MIM# 620194
Intellectual disability syndromic and non-syndromic v0.5153 SMC5 Zornitza Stark Phenotypes for gene: SMC5 were changed from Multiple congenital anomalies/dysmorphic syndrome, MONDO:0019042, SLF2-related; Atelis syndrome; microcephaly; short stature; ID to Atelis syndrome 2, MIM# 620185
Intellectual disability syndromic and non-syndromic v0.5152 SLF2 Zornitza Stark Phenotypes for gene: SLF2 were changed from Multiple congenital anomalies/dysmorphic syndrome, MONDO:0019042, SLF2-related; Atelis syndrome; microcephaly; short stature; ID to Atelis syndrome 1, MIM# 620184
Intellectual disability syndromic and non-syndromic v0.5148 TRPC5 Zornitza Stark gene: TRPC5 was added
gene: TRPC5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TRPC5 was set to X-LINKED: hemizygous mutation in males, biallelic mutations in females
Publications for gene: TRPC5 were set to 36323681; 24817631; 23033978; 33504798; 28191890
Phenotypes for gene: TRPC5 were set to Neurodevelopmental disorder, MONDO:0700092, TRPC5-related
Review for gene: TRPC5 was set to AMBER
Added comment: PMID: 36323681; Leitão E. et al. (2022) Nat Commun.13(1):6570:
Missense variant NM_012471.2:c.523C>T, p.(Arg175Cys in three brothers with intellectual disability (ID) and autistic spectrum disorder (ASD), inherited from an asymptomatic mother and absent in the maternal grandparents.
Whole cell patch clamp studies of HEK293 created by site-directed mutagenesis showed increased current of this calcium channel (constitutively opened).
(This variant is absent in gnomAD v2.1.1).

Also, the nonsense variant, c.965G> A, p.(Trp322*) was found in a high functioning ASD male (maternally inherited), NMD-predicted.

Other papers and TRPC5 variants that were cited to associate this gene with X-linked ID and/or ASD include:
PMID: 24817631; Mignon-Ravix, C. et al. (2014) Am. J.Med. Genet. A 164A: 1991–1997: A hemizygous 47-kb deletion in Xq23 including exon 1 of the TRPC5 gene. He had macrocephaly, delayed psychomotor development, speech delay, behavioural problems, and autistic features. Maternally inherited, and a family history compatible with X-linked inheritance (i.e., maternal great uncle was also affected, although not tested).

In addition, PMID: 36323681; Leitão E. et al. (2022) cites papers with the variants p.(Pro667Thr), p.(Arg71Gln) and p.(Trp225*).
NB. p.(Pro667Thr) is absent in gnomAD (v2.1.1), p.(Arg71Gln) is also absent (the alternative variant p.(Arg71Trp) is present once as heterozygous only). p.(Trp225*) is absent, and it should be noted that PTCs / LoF variants are very rare (pLI = 1).

However, looking further into the three references, the evidence is not as clear or as accurate as was stated.

The missense variant c.1999C>A, p.(Pro667Thr), was stated as de novo, but was actually maternally inherited but was still considered a candidate for severe intellectual disability (shown in the Appendix, Patient 93, with severe speech delay, autism spectrum disorder and Gilles de la Tourette). This patient also has a de novo MTF1 variant. Reference: PMID: 23033978; de Ligt, J. et al. (2012) N. Engl. J. Med. 367: 1921–1929).

Missense variant (de novo): c.212G>A, p.(Arg71Gln), was found as part of the Deciphering Developmental Disorders (DDD) study and is shown in individual 164 in Supplementary Table 2 of PMID: 33504798; Martin, HC. et al. (2021) Nat. Commun.12: 627. Also displayed in DECIPHER (DDD research variant) with several phenotype traits, but ID and ASD are not specifically mentioned.

Nonsense variant: c.674G>A. p.(Trp225*) was stated as de novo but was inherited (reference PMID: 28191890; Kosmicki, JA. et al. (2017) Nat. Genet. 49: 504–510. Supplement Table 7). This was a study of severe intellectual delay, developmental delay / autism. (NB. The de novo p.(Arg71Gln) variant from the DDD study is also listed (subject DDD 342 in Supplement 4 / Table 2).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5134 TRA2B Elena Savva gene: TRA2B was added
gene: TRA2B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TRA2B was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: TRA2B were set to PMID: 36549593
Phenotypes for gene: TRA2B were set to Neurodevelopmental disorder, TRA2B-related (MONDO#0700092)
Review for gene: TRA2B was set to GREEN
Added comment: PMID: 36549593
- 12 individuals with ID and dev delay. Additional features include infantile spams 6/12, hypotonia 12/12, dilated brain ventricles 6/12, microcephaly 5/12
- All variants result in the loss of 1/2 transcripts (start-losses or PTCs upstream of a second translation start position). Shorter transcript expression is increased, longer transcript expression is decreased.
- Apparently het mice K/O are normal, but complete K/O cannot develop embryonically.
- DN mechanism suggested
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5133 BUB1 Zornitza Stark Phenotypes for gene: BUB1 were changed from Neurodevelopmental disorder, BUB1-related MONDO:0700092; Intellectual disability and microcephaly to Primary microcephaly-30 (MCPH30), MIM#620183
Intellectual disability syndromic and non-syndromic v0.5132 BUB1 Zornitza Stark reviewed gene: BUB1: Rating: AMBER; Mode of pathogenicity: None; Publications: ; Phenotypes: Primary microcephaly-30 (MCPH30), MIM#620183; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5131 CLDN5 Zornitza Stark Phenotypes for gene: CLDN5 were changed from seizures; developmental delay; microcephaly; brain calcifications to Syndromic disorder, MONDO:0002254, CLDN5-related
Intellectual disability syndromic and non-syndromic v0.5127 SETD2 Zornitza Stark edited their review of gene: SETD2: Added comment: PMID 32710489: 12 unrelated patients, ranging from 1 month to 12 years of age, with a multisystemic neurodevelopmental disorder associated with a specific de novo heterozygous mutation in the SETD2 gene (R1740W).

Key clinical features: severely impaired global development apparent from infancy, feeding difficulties with failure to thrive, small head circumference, and dysmorphic facial features. Affected individuals have impaired intellectual development and hypotonia; they do not achieve walking or meaningful speech. Other neurologic findings may include seizures, hearing loss, ophthalmologic defects, and brain imaging abnormalities. There is variable involvement of other organ systems, including skeletal, genitourinary, cardiac, and possibly endocrine.

Further 3 unrelated patients identified with mild to moderately impaired intellectual development associated with a specific de novo heterozygous mutation in the SETD2 gene (R1740Q).

These are distinct clinically from Luscan-Lumish syndrome, which is characterised by overgrowth.; Changed publications: 29681085, 32710489; Changed phenotypes: Luscan-Lumish syndrome, MIM#616831, Rabin-Pappas syndrome,MIM# 620155, Intellectual developmental disorder, autosomal dominant 70, MIM# 620157
Intellectual disability syndromic and non-syndromic v0.5127 CLDN5 Suliman Khan gene: CLDN5 was added
gene: CLDN5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CLDN5 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CLDN5 were set to PMID: 36477332
Phenotypes for gene: CLDN5 were set to seizures; developmental delay; microcephaly; brain calcifications
Penetrance for gene: CLDN5 were set to Complete
Mode of pathogenicity for gene: CLDN5 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: CLDN5 was set to GREEN
Added comment: PMID: 36477332 identified de novo heterozygous missense variants in CLDN5 in fifteen unrelated patients who presented with a shared constellation of features including developmental delay, seizures (primarily infantile onset focal epilepsy), microcephaly and a recognizable pattern of pontine atrophy and brain calcifications.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5123 CACNA2D1 Zornitza Stark Phenotypes for gene: CACNA2D1 were changed from Developmental and epileptic encephalopathy disorder MONDO:0100062 CACNA2D1-related to Developmental and epileptic encephalopathy 110, MIM# 620149
Intellectual disability syndromic and non-syndromic v0.5122 CACNA2D1 Zornitza Stark reviewed gene: CACNA2D1: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 110, MIM# 620149; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5121 FZR1 Zornitza Stark gene: FZR1 was added
gene: FZR1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: FZR1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: FZR1 were set to 34788397
Phenotypes for gene: FZR1 were set to Developmental and epileptic encephalopathy 109, MIM# 620145
Review for gene: FZR1 was set to GREEN
Added comment: Four unrelated individuals reported with de novo missense variants in this gene. Affected individuals had developmental delay before and concurrent with the onset of seizures. Features included impaired intellectual development with poor speech, ataxic gait, coordination problems, and behavioral abnormalities. Drosophila model supports gene-disease association.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.5079 DPM1 Sindhu V changed review comment from: More than 3 unrelated families with consistent phenotype of developmental delay, hypotonia , seizures, (acquired) microcephaly, vision impairment with/without elevated CK and cerebellar signs. Molecular evidence of biallelic involvement with missense, deletion and splice site variants as contributory mechanisms. Quantification of isoform consistent with CDG 1E pattern.; to: More than 3 unrelated families with consistent phenotype of developmental delay, hypotonia , seizures, (acquired) microcephaly, vision impairment with/without elevated CK and cerebellar signs. Molecular evidence of biallelic involvement with missense, deletion and splice site variants as contributory mechanisms. Quantification of isoform consistent with CDG 1E pattern.
Intellectual disability syndromic and non-syndromic v0.5079 DPM1 Sindhu V reviewed gene: DPM1: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 10642602, 23856421, 16641202, 15669674, 10642597; Phenotypes: Acquired microcephaly, developmental delay, epilepsy, strabismus, hypotonia, cortical vision impairment, elevated creatine kinase, growth failure; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.5053 EPRS Lucy Spencer gene: EPRS was added
gene: EPRS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: EPRS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: EPRS were set to 29576217, 36411955
Phenotypes for gene: EPRS were set to Leukodystrophy, hypomyelinating, 15 (MIM#617951)
Review for gene: EPRS was set to GREEN
Added comment: 5 patients across 2 papers, with delayed development (3/5) and/or regression, ataxia, dystonia, hypomyelinating leukodystrophy or periventricular white matter, 2 with epilepsy, 3 with optic atrophy, 2 with deafness, 2 with micrcephaly, 1 noted to have some facial dysmorphism.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5041 ARPC4 Zornitza Stark gene: ARPC4 was added
gene: ARPC4 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ARPC4 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ARPC4 were set to 35047857
Phenotypes for gene: ARPC4 were set to Developmental delay, language impairment, and ocular abnormalities, MIM# 620141
Review for gene: ARPC4 was set to GREEN
Added comment: 7 affected individuals from 6 families (gonadal mosaicism was confirmed in the mother of the 2 affected siblings) with a recurrent missense variant (NM_005718.4:c.472C>T; p.R158C). 6/7 affected individuals had microcephaly. The variant was associated with a decreased amount of F-actin in cells from two affected individuals.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5031 KIF26A Chirag Patel gene: KIF26A was added
gene: KIF26A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: KIF26A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: KIF26A were set to PMID: 36228617
Phenotypes for gene: KIF26A were set to Congenital brain malformations, no OMIM #
Review for gene: KIF26A was set to GREEN
Added comment: 5 unrelated patients with biallelic loss-of-function variants in KIF26A (found through WES), exhibiting a spectrum of congenital brain malformations (schizencephaly, corpus callosum anomalies, polymicrgyria, and ventriculomegaly). Combining mice and human iPSC-derived organoid models, they discovered that loss of KIF26A causes excitatory neuron-specific defects in radial migration, localization, dendritic and axonal growth, and apoptosis, offering a convincing explanation of the disease etiology in patients. Single-cell RNA sequencing in KIF26A knockout organoids revealed transcriptional changes in MAPK, MYC, and E2F pathways.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5025 TPR Zornitza Stark gene: TPR was added
gene: TPR was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TPR was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TPR were set to 34494102
Phenotypes for gene: TPR were set to Multiple congenital anomalies/dysmorphic syndrome, MONDO:0019042, TPR-related
Review for gene: TPR was set to RED
Added comment: Two siblings harbouring variants c.6625C>T/ p.Arg2209Ter (identified in heterozygous state in both siblings and father) and c.2610 + 5G > A (identified in heterozygous state in both siblings and mother) were reported with ataxia, microcephaly and severe intellectual disability. Functional analyses in patient fibroblasts provide evidence that the variants affect TPR splicing, reduce steady-state TPR levels, abnormal nuclear pore composition and density, and altered global RNA distribution.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5023 SMC5 Zornitza Stark gene: SMC5 was added
gene: SMC5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SMC5 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SMC5 were set to 36333305
Phenotypes for gene: SMC5 were set to Multiple congenital anomalies/dysmorphic syndrome, MONDO:0019042, SLF2-related; Atelis syndrome; microcephaly; short stature; ID
Review for gene: SMC5 was set to GREEN
Added comment: Four individuals from three families with a chromosome breakage disorder and bi-allelic variants in this gene. However, three of the individuals had the same homozygous missense variant. Evidence for functional impact of the variant was limited. However, zebrafish model recapitulated the phenotype and was not rescued by the introduction of this variant, arguing for functional effect. Borderline Amber/Green.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5021 SLF2 Zornitza Stark gene: SLF2 was added
gene: SLF2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SLF2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLF2 were set to 36333305
Phenotypes for gene: SLF2 were set to Multiple congenital anomalies/dysmorphic syndrome, MONDO:0019042, SLF2-related; Atelis syndrome; microcephaly; short stature; ID
Review for gene: SLF2 was set to GREEN
Added comment: Seven individuals from 6 families with a chromosome breakage disorder and bi-allelic variants in this gene (LoF). Functional data including zebrafish model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5020 MAST3 Zornitza Stark Phenotypes for gene: MAST3 were changed from Developmental and epileptic encephalopathy to Developmental and epileptic encephalopathy 108, MIM#620115
Intellectual disability syndromic and non-syndromic v0.5019 MAST3 Zornitza Stark edited their review of gene: MAST3: Changed phenotypes: Developmental and epileptic encephalopathy 108, MIM#620115
Intellectual disability syndromic and non-syndromic v0.5011 CAMSAP1 Naomi Baker gene: CAMSAP1 was added
gene: CAMSAP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CAMSAP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CAMSAP1 were set to 36283405
Phenotypes for gene: CAMSAP1 were set to lissencephaly spectrum disorders (MONDO:0018838), CAMSAP1-related
Review for gene: CAMSAP1 was set to GREEN
Added comment: Five unrelated families with bi-allelic loss-of-function variants. Clinical features of the syndrome include a characteristic craniofacial appearance, primary microcephaly, lissencephaly, agenesis or severe hypogenesis of the corpus callosum, severe neurodevelopmental delay, cortical visual impairment, and seizures.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.5003 AKT3 Zornitza Stark Phenotypes for gene: AKT3 were changed from to Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2, MIM# 615937
Intellectual disability syndromic and non-syndromic v0.5000 AKT3 Zornitza Stark reviewed gene: AKT3: Rating: GREEN; Mode of pathogenicity: None; Publications: 22729224, 22729223, 35665751, 34354878, 32446860, 31441589; Phenotypes: Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2, MIM# 615937; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4980 GABRG1 Zornitza Stark Phenotypes for gene: GABRG1 were changed from to Developmental and epileptic encephalopathy MONDO:0100062
Intellectual disability syndromic and non-syndromic v0.4970 GABRG1 Anna Ritchie reviewed gene: GABRG1: Rating: RED; Mode of pathogenicity: None; Publications: PMID: 36121006; Phenotypes: Developmental and epileptic encephalopathy MONDO:0100062; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4968 SLC32A1 Lucy Spencer gene: SLC32A1 was added
gene: SLC32A1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SLC32A1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SLC32A1 were set to 36073542
Phenotypes for gene: SLC32A1 were set to developmental and epileptic encephalopathy MONDO:0100062, SLC32A1-related
Review for gene: SLC32A1 was set to GREEN
Added comment: PMID: 36073542- 4 patients with de novo missense. All have moderate to severe ID or developmental delay and seizures. 3 have a movement disorder. Developmental delay appears to be a new association for this gene described in this paper.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4966 GCSH Ain Roesley Phenotypes for gene: GCSH were changed from Glycine encephalopathy, MIM#605899 to Glycine encephalopathy MIM#605899; neurodevelopmental disorder MONDO#0700092, GCHS-related
Intellectual disability syndromic and non-syndromic v0.4965 GCSH Ain Roesley reviewed gene: GCSH: Rating: GREEN; Mode of pathogenicity: None; Publications: 36190515; Phenotypes: Glycine encephalopathy MIM#605899, neurodevelopmental disorder MONDO#0700092, GCHS-related; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.4965 MTSS1 Elena Savva gene: MTSS1 was added
gene: MTSS1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MTSS1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MTSS1 were set to PMID: 36067766
Phenotypes for gene: MTSS1 were set to Intellectual disability, MTSS1-related (MONDO#0001071)
Review for gene: MTSS1 was set to GREEN
Added comment: Alt gene name: MTSS2

Huang (2022): recurring de novo missense variant (p.R671W) causing syndromic intellectual disability in 5 unrelated individuals.
- Individuals present with GDD, mild ID (5/5), nystagmus (3/5), optic atrophy (1/5), ptosis (2/5), sensorineural hearing loss (2/4), microcephaly or relative microcephaly (5/5), and shared mild facial dysmorphisms.
- Overexpression supports a DN mechanism
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4964 MTSS1L Elena Savva gene: MTSS1L was added
gene: MTSS1L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MTSS1L was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MTSS1L were set to PMID: 36067766
Phenotypes for gene: MTSS1L were set to Intellectual disability, MTSS2-related (MONDO#0001071)
Review for gene: MTSS1L was set to GREEN
Added comment: Alt gene name: MTSS2

Huang (2022): recurring de novo missense variant (p.R671W) causing syndromic intellectual disability in 5 unrelated individuals.
- Individuals present with GDD, mild ID (5/5), nystagmus (3/5), optic atrophy (1/5), ptosis (2/5), sensorineural hearing loss (2/4), microcephaly or relative microcephaly (5/5), and shared mild facial dysmorphisms.
- Overexpression supports a DN mechanism
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4963 NAPB Paul De Fazio gene: NAPB was added
gene: NAPB was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NAPB was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NAPB were set to 26235277; 28097321; 33189936
Phenotypes for gene: NAPB were set to Developmental and epileptic encephalopathy 107 MIM#620033
Review for gene: NAPB was set to GREEN
gene: NAPB was marked as current diagnostic
Added comment: PMID 26235277: homozygous nonsense variant identified in a 6 year old girl by trio WES with early-onset epileptic encephalopathy characterised by multifocal seizures and profound GDD

PMID 28097321: exome sequencing in 152 consanguineous families with at least one member affected with ID. Homozygous nonsense variant identified in a patient with profound ID, seizures, feeding difficulties in infancy, muscularhypotonia, microcephaly, and impaired vision

PMID 33189936: homozygous canonical splice variant identified by trio exome sequencing in two siblings with seizures, intellectual disability and global developmental delay, microcephaly (<-3SD), and muscular hypotonia.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4962 RABGAP1 Zornitza Stark gene: RABGAP1 was added
gene: RABGAP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RABGAP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: RABGAP1 were set to 36083289
Phenotypes for gene: RABGAP1 were set to Neurodevelopmental disorder, RABGAP1-related,MONDO:0700092
Review for gene: RABGAP1 was set to GREEN
Added comment: 5 individuals from three families reported with ID, microcephaly, SNHL and seizures. Mouse model recapitulated the phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4961 NSD2 Zornitza Stark Phenotypes for gene: NSD2 were changed from Rauch-Steindl syndrome, MIM# 619695; Microcephaly; intellectual disability to Rauch-Steindl syndrome, MIM# 619695; Microcephaly; intellectual disability; Neurodevelopmental disorder, NSD2-associated, GoF, MONDO:0700092
Intellectual disability syndromic and non-syndromic v0.4959 NSD2 Zornitza Stark edited their review of gene: NSD2: Added comment: PMID 36189577: two individuals reported with a GoF variant, p.Glu1099Lys, and a distinct phenotype: intellectual disability, coarse/ square facial gestalt, abnormalities of the hands, and organomegaly.; Changed publications: 30345613, 31171569, 36189577; Changed phenotypes: Rauch-Steindl syndrome, MIM# 619695, Microcephaly, intellectual disability, Neurodevelopmental disorder, NSD2-associated, GoF, MONDO:0700092
Intellectual disability syndromic and non-syndromic v0.4959 DOHH Zornitza Stark Phenotypes for gene: DOHH were changed from Neurodevelopmental disorder, DOHH-related (MONDO#0700092) to Neurodevelopmental disorder with microcephaly, cerebral atrophy, and visual impairment, MIM# 620066
Intellectual disability syndromic and non-syndromic v0.4958 DOHH Zornitza Stark reviewed gene: DOHH: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, cerebral atrophy, and visual impairment, MIM# 620066; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4947 PDCD6IP Zornitza Stark Phenotypes for gene: PDCD6IP were changed from Primary microcephaly to Microcephaly 29, primary, autosomal recessive, MIM# 620047
Intellectual disability syndromic and non-syndromic v0.4946 PDCD6IP Zornitza Stark reviewed gene: PDCD6IP: Rating: AMBER; Mode of pathogenicity: None; Publications: ; Phenotypes: Microcephaly 29, primary, autosomal recessive, MIM# 620047; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4939 PPP2R5C Zornitza Stark Phenotypes for gene: PPP2R5C were changed from macrocephaly; intellectual disability to Neurodevelopmental disorder, PPP2R5C-related (MONDO:070092); macrocephaly; intellectual disability
Intellectual disability syndromic and non-syndromic v0.4935 UFSP2 Zornitza Stark Phenotypes for gene: UFSP2 were changed from Abnormal muscle tone; Seizures; Global developmental delay; Delayed speech and language development; Intellectual disability; Strabismus to Developmental and epileptic encephalopathy 106, MIM# 620028; Abnormal muscle tone; Seizures; Global developmental delay; Delayed speech and language development; Intellectual disability; Strabismus
Intellectual disability syndromic and non-syndromic v0.4934 UFSP2 Zornitza Stark edited their review of gene: UFSP2: Changed phenotypes: Developmental and epileptic encephalopathy 106, MIM# 620028, Abnormal muscle tone, Seizures, Global developmental delay, Delayed speech and language development, Intellectual disability, Strabismus
Intellectual disability syndromic and non-syndromic v0.4934 TRAPPC10 Zornitza Stark Phenotypes for gene: TRAPPC10 were changed from neurodevelopmental disorder (MONDO:0700092), TRAPPC10-related to Neurodevelopmental disorder with microcephaly, short stature, and speech delay, MIM# 620027
Intellectual disability syndromic and non-syndromic v0.4933 TRAPPC10 Zornitza Stark reviewed gene: TRAPPC10: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, short stature, and speech delay, MIM# 620027; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4932 UBAP2L Zornitza Stark Phenotypes for gene: UBAP2L were changed from Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system to Neurodevelopmental disorder, MONDO:0700092, UBAP2L-related; Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system
Intellectual disability syndromic and non-syndromic v0.4929 CHKA Zornitza Stark Phenotypes for gene: CHKA were changed from Neurodevelopmental disorder, MONDO:0700092; Abnormal muscle tone; Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormality of movement; Abnormality of nervous system morphology; Short stature to Neurodevelopmental disorder with microcephaly, movement abnormalities, and seizures, MIM#620023
Intellectual disability syndromic and non-syndromic v0.4928 CHKA Zornitza Stark reviewed gene: CHKA: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, movement abnormalities, and seizures, MIM#620023; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4928 UBAP2L Konstantinos Varvagiannis gene: UBAP2L was added
gene: UBAP2L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: UBAP2L was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: UBAP2L were set to 35977029
Phenotypes for gene: UBAP2L were set to Delayed speech and language development; Motor delay; Intellectual disability; Autistic behavior; Seizures; Microcephaly; Abnormality of head or neck; Short stature; Abnormality of the skeletal system
Penetrance for gene: UBAP2L were set to unknown
Review for gene: UBAP2L was set to GREEN
Added comment: Based on Jia et al (2022 - PMID: 35977029) speech, motor delay as well as ID are observed in individuals harboring de novo pLoF variants in UBAP2L. The gene encodes a regulator of the stress granule (SG) assembly. Extensive evidence is provided on the effect of variants as well as the role of UBAP2L and other genes for components and/or regulation of SG in pathogenesis of NDDs. Among others a Ubap2l htz deletion mouse model (behavioral and cognitive impairment, abnormal cortical development due to impaired SG assembly, etc). Data from 26 previous studies, aggregating 40,853 probands with NDDs (mostly DD/ID, also ASD) suggest enrichment for DNMs in UBAP2L or other genes previously known and further shown to be important for SG formation (incl. G3BP1/G3BP2, CAPRIN1).

Details provided below.

Not associated with any phenotype in OMIM, G2P or SysNDD.

--------

Jia et al (2022 - PMID: 35977029) describe 12 affected individuals with heterozygous de novo pLoF variants in UBAP2L.

Phenotype: Features included hypotonia, speech (11/11) and motor delay (8/12), ID (8/10 with formal evaluation), variable behavioral concerns (ADHD 5/11, ASD in 4/10, etc). Seizures were reported in 7/12 with 3/10 having a formal diagnosis of epilepsy. Few had microcephaly (3/10). Facial dysmorphisms were common (9/9) and included abnormal palpebral fissures, deep prominent concha, high broad forehead, hypertelorism, thin upper lip and mild synophrys (each in 4 or less individuals). Short stature or skeletal alterations were described in some (4/10 each).

Role of the gene: UBAP2L encodes an essential regulator of stress granule assembly. Stress granules are membraneless cytoplasmic compartments in eukaryotic cells, induced upon a variety of stressors and playing a role in regulation of gene expression.

Variants identified : 9 nonsense/frameshift UBAP2L variants and 3 splicing ones were reported, in all cases as de novo events, upon trio/quad exome sequencing. All were absent from gnomAD. There were no other causative variants.

Variant effect/studies (NM_014847.4 / NP_055662.3) :
- Minigene assays revealed that the 3 splice variants all resulted in out-of-frame exon skipping.
- In patient fibroblasts one of these splice variants was demonstrated to result to reduced protein levels.
- 8 of the 9 nonsense/frameshift variants were predicted to result to NMD.
- 1 nonsense variant (c.88C>T/p.Q30*) was shown to result to decreased protein expression in patient fibroblasts, with detection of the protein using an antibody for the C terminus but not the N terminus. Protein N-terminal sequencing confirmed that the protein lacked the N terminus, with utilization of an alternative start site (11 codons downstream).
- Generation of HeLa UBAP2L KO cell lines resulted in significant reduction of SG numbers which was also the case for 4 variants studied, under stress conditions.
- The protein has a DUF domain (aa 495-526) known to mediate interaction of UBAP2L with G3BP1 (a stress granule marker) with deletions of this domain leading to shuttling of UBAP2L from the cytoplasm to the nucleus. Truncating variants upstream of the DUF domain were shown to result in nuclear localization.

Mouse model :
- The authors generated Ubap2l KO model with hmz deletion of Ubap2l resulting in a lethal phenotype (2.6% survived) and htz deletion leading to behavioral issues (low preference for social novelty, anxious-like behaviors) and cognitive impairment.
- Ubap2l haploinsufficiency resulted in abnormal cortical development and lamination with reduction of neural progenitor proliferation.
- Ubap2l deficiency was shown to impair SG assembly during cortical development both under physiological stress conditions or upon utilization of an oxidative stress inducer.

Additional evidence of UBAP2L and SG overall in pathogenesis of NDDs:
- Based on DNMs from 40,853 individuals with NDDs from 26 studies (9,228 with ASD, 31,625 with DD/ID) the authors demonstrate significant excess of DNM in 31 genes encoding SG components, regulators or both, the latter being the case for UBAP2L and 2 further genes (G3BP1 and G3BP2 - both with crucial roles in SG assembly).
- Excess dn splice-site (N=3) and missense (N=5) variants in G3BP1 were observed in the above cohort [c.95+1G>A, c.353+1G>T, c.539+1G>A / p.S208C, R320C, V366M].
- Excess dn missense (N=7) variants in G3BP2 were observed in the above cohort [p.R13W, D151N, E158K, L209P, E399D, K408E, R438C].
- Generation of G3BP1 or G3BP2 KO HeLa cell lines and immunofluorescence upon use of oxidative stress inducer revealed significant reduction of stress granules.
- Generation of HeLa cell lines for 5 G3BP1 mutants (R78C*, R132I*, S208C*, R320C*, V366M) and 7 G3BP2 mutants (p.R13W*, D151N*, E158K, L209P*, E399D, K408E, R438C) revealed that several (those in asterisk) resulted in significantly fewer SG formation under oxidative stress compared to WT while the subcellular distribution of the proteins under stress was identical to WT.
- Among the identified genes for SG enriched for DNMs, CAPRIN1 was implicated in previous publications as a NDD risk gene with 3 dn missense SNVs reported (p.I373K, p.Q446H, p.L484P). CAPRIN1 binding to G3BP1/2 has been shown to promote SG formation. Significant reduction of SG was observed in CAPRIN1 KO HeLa lines. p.I373K abolished interaction with G3BP1/2 and disrupted SG formation.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4927 PPFIBP1 Zornitza Stark Phenotypes for gene: PPFIBP1 were changed from Neurodevelopmental disorder, MONDO:0700092, PPFIBP1-related to Neurodevelopmental disorder with seizures, microcephaly, and brain abnormalities, MIM# 620024
Intellectual disability syndromic and non-syndromic v0.4926 PPFIBP1 Zornitza Stark edited their review of gene: PPFIBP1: Changed phenotypes: Neurodevelopmental disorder with seizures, microcephaly, and brain abnormalities, MIM# 620024
Intellectual disability syndromic and non-syndromic v0.4924 SLC31A1 Daniel Flanagan gene: SLC31A1 was added
gene: SLC31A1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: SLC31A1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLC31A1 were set to PMID: 35913762
Phenotypes for gene: SLC31A1 were set to Neurodevelopmental disorder, SLC31A1-related (MONDO#0700092)
Review for gene: SLC31A1 was set to RED
Added comment: SLC31A1 is also referred to as CTR1.
Monozygotic twins with hypotonia, global developmental delay, seizures, and rapid brain atrophy, consistent with profound central nervous system copper deficiency. Homozygous for a novel missense variant (p.(Arg95His)) in copper transporter CTR1, both parents heterozygous. A mouse knock-out model of CTR1 deficiency resulted in prenatal lethality.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.4915 COX11 Chern Lim gene: COX11 was added
gene: COX11 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: COX11 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: COX11 were set to 36030551
Phenotypes for gene: COX11 were set to Mitochondrial disease (MONDO:0044970), COX11-related
Review for gene: COX11 was set to GREEN
gene: COX11 was marked as current diagnostic
Added comment: PMID: 36030551
- Biallelic variants in COX11 associated with infantile-onset mitochondrial encephalopathies in two unrelated consanguineous families, one with homozygous missense variant, another with homozygous frameshift variant.
- Functional studies supported pathogenicity of the missense variant, and showed that mutant COX11 fibroblasts had decreased ATP levels which could be rescued by CoQ10.
- RNA studies suggested the mutant transcript with p.(Val12Glyfs*21) is not degraded by nonsense mediated decay.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4912 NOTCH1 Chern Lim changed review comment from: PMID: 35947102:
- Seven unrelated patients with leukoencephalopathy and calcifications, germline heterozygous de novo gain-of-function variants in NOTCH1.
- Missense and small inframe insertion variants in the negative regulatory region.
Sources: Literature; to: PMID: 35947102:
- Seven unrelated patients with leukoencephalopathy and calcifications, germline heterozygous de novo gain-of-function variants in NOTCH1.
- Other clinical features include intellectual disability, spasticity and etc. Childhood onset in most individuals however 15y and 40y reported in two individuals.
- Missense and small inframe insertion variants in the negative regulatory region.
Intellectual disability syndromic and non-syndromic v0.4912 NOTCH1 Chern Lim gene: NOTCH1 was added
gene: NOTCH1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NOTCH1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: NOTCH1 were set to 35947102
Phenotypes for gene: NOTCH1 were set to Genetic cerebral small vessel disease (MONDO:0018787), NOTCH1-related
Mode of pathogenicity for gene: NOTCH1 was set to Other
Review for gene: NOTCH1 was set to GREEN
gene: NOTCH1 was marked as current diagnostic
Added comment: PMID: 35947102:
- Seven unrelated patients with leukoencephalopathy and calcifications, germline heterozygous de novo gain-of-function variants in NOTCH1.
- Missense and small inframe insertion variants in the negative regulatory region.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4872 PSMC1 Hazel Phillimore gene: PSMC1 was added
gene: PSMC1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PSMC1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PSMC1 were set to PMID: 35861243
Phenotypes for gene: PSMC1 were set to spastic paraplegia; severe developmental delay; severe intellectual disability; hearing loss; micropenis; undescended testes; Syndromic disease MONDO:0002254, PSMC1-related
Review for gene: PSMC1 was set to RED
Added comment: Homozygosity mapping on one large consanguineous Bedouin kindred showed three affected children (out of the ten) to be homozygous for NM_002802.3:c.983T>C; p.(Ile328Thr).

Drosophila rescue experiments were carried out. Transgenic studies using drosophila with the silenced ortholog Rpt2 gene were rescued by the human wild-type PSMC1.

Three of the ten offspring of healthy consanguineous parents of Bedouin Israeli ancestry were affected with a similar phenotype of failure to thrive, developmental delay and severe intellectual disability, spastic tetraplegia with central hypotonia, chorea, as well as hearing loss. None of the three achieved verbal communication or ambulation (sitting / standing) at any age. They had mild dysmorphism of borderline dolichocephaly and microcephaly, prominent bushy eyebrows, flat midface, long nasal bridge and micrognathia. All three had micropenis with undescended testes. One of the affected (as a toddler) underwent thorough endocrinological analysis: testosterone and gonadotropin levels were low.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4867 WARS Anna Ritchie gene: WARS was added
gene: WARS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: WARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: WARS were set to PMID: 35815345; 35790048
Phenotypes for gene: WARS were set to Neurodevelopmental disorder (MONDO:0700092), WARS-related
Review for gene: WARS was set to GREEN
Added comment: At least seven affected individuals from four families with biallelic variants, showing varying
severities of developmental delay, intellectual disability and microcephaly. Hearing impairment and, as well as brain anomalies, skeletal system, movement/gait, and behaviour were variable features.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4865 DOHH Daniel Flanagan gene: DOHH was added
gene: DOHH was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: DOHH was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DOHH were set to PMID: 35858628
Phenotypes for gene: DOHH were set to Neurodevelopmental disorder, DOHH-related (MONDO#0700092)
Review for gene: DOHH was set to GREEN
Added comment: Bi-allelic missense and truncating DOHH variants segregating with disease in five affected individuals from four unrelated families. Clinical features were developmental delay and/or intellectual disability (5/5), microcephaly (5/5), visual impairment (nystagmus (3/5), strabismus (3/5), and cortical visual impairment (1/5)) and congenital heart malformations (3/5 individuals).
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.4854 KMT2B Zornitza Stark edited their review of gene: KMT2B: Added comment: Nine individuals reported in PMID 33150406 with heterozygous variants in this gene and intellectual disability, speech delay, microcephaly, growth delay, feeding problems, and dysmorphic features, including epicanthic folds, posteriorly rotated ears, syndactyly/clinodactyly of toes, and fifth finger clinodactyly, normal MRIs and NO dystonia.; Changed publications: 33150406; Changed phenotypes: Dystonia 28, childhood-onset 617284, MONDO:0015004, Intellectual developmental disorder, autosomal dominant 68, MIM# 619934
Intellectual disability syndromic and non-syndromic v0.4843 WNK3 Lucy Spencer gene: WNK3 was added
gene: WNK3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: WNK3 was set to X-LINKED: hemizygous mutation in males, biallelic mutations in females
Publications for gene: WNK3 were set to 35678782
Phenotypes for gene: WNK3 were set to Neurodevelopmental disorder, WNK3-related (MONDO#0700092)
Review for gene: WNK3 was set to GREEN
Added comment: 6 maternally inherited hemizygous variants, 3 missense, 2 canonical splice, and a nonsense. Seen in 14 individuals from 6 families, all 14 are male who inherited hemizygous variants from their unaffected heterozygous mothers. The variants cosegregated with disease in 3 families with multiple affected individuals. All 14 patients have ID, 11 have speech delay, 10 have facial abnormalities, 5 have seizures, 6 with microcephaly and 7 with anomalies in brain imaging.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4839 TAF8 Zornitza Stark changed review comment from: Further 7 individuals reported from 4 families, three of which were consanguineous.

Clinical features included severe psychomotor retardation with almost absent development, feeding problems, microcephaly, growth retardation, spasticity and epilepsy.

Five had the previously reported c.781-1G > A variant in homozygous state. This is likely to be a founder variant.

One family with different compound heterozygous variants.; to: Further 7 individuals reported from 4 families, three of which were consanguineous.

Clinical features included severe psychomotor retardation with almost absent development, feeding problems, microcephaly, growth retardation, spasticity and epilepsy.

Five had the previously reported c.781-1G > A variant in homozygous state. Unclear if this is a founder variant, families of different ethnicities.

One family with different compound heterozygous variants.
Intellectual disability syndromic and non-syndromic v0.4826 KCNC2 Zornitza Stark gene: KCNC2 was added
gene: KCNC2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: KCNC2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: KCNC2 were set to 32392612; 31972370; 35314505
Phenotypes for gene: KCNC2 were set to Developmental and epileptic encephalopathy 103, MIM# 619913
Review for gene: KCNC2 was set to GREEN
Added comment: More than 10 unrelated families reported. ID ranges from mild to severe.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.4818 PAN2 Naomi Baker gene: PAN2 was added
gene: PAN2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PAN2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PAN2 were set to PMID:35304602; 29620724
Phenotypes for gene: PAN2 were set to Syndromic disease MONDO:0002254
Review for gene: PAN2 was set to GREEN
Added comment: PMID:35304602 reports five individuals from 3 families with biallelic (homozygous) loss-of-function variants. Clinical presentation incudes mild-moderate intellectual disability, hypotonia, sensorineural hearing loss, EEG abnormalities, congenital heart defects (tetralogy of Fallot, septal defects, dilated aortic root), urinary tract malformations, ophthalmological anomalies, short stature with other skeletal anomalies, and craniofacial features including flat occiput, ptosis, long philtrum, and short neck.

PMID:29620724 reports one individual with biallelic (homozygous) loss-of-function variant who presented with global developmental delay, mild hypotonia, craniosynostosis, severe early-onset scoliosis, imperforate anus, and double urinary collecting system.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4814 PRPF8 Krithika Murali gene: PRPF8 was added
gene: PRPF8 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PRPF8 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PRPF8 were set to 35543142
Phenotypes for gene: PRPF8 were set to Intellectual disability; epilepsy; Retinitis pigmentosa 13 - MIM#600059
Review for gene: PRPF8 was set to GREEN
Added comment: PMID 35543142 O'Grady et al 2022 report 14 unrelated individuals with heterozygous PRPF8 variants and ID, dymorphic features and epilepsy (7/14). Short stature, abnormal gait and cardiac anomalies also reported. 11 variants identified were de novo, 1 variant - maternal mosaicism, 1 variant - duo sequencing (not identified in mother, father could not be sequenced). 1 individual did not have parental testing. Cardiac anomalies varied and included benign cardiac tumour, dilated cardiomyopathy, dilated aortic root (COL5A2 VUS also identified), bicuspid aortic valve, cardiac arrest, self-resolving ASD/VSD.

Heterozygous PRPF8 variants previously associated with retinitis pigmentosa. 1 out of the 14 individuals in this cohort had a diagnosis of RP. RP variants noted to cluster in the C'terminal MPN domain. The individual with RP in this paper had a variant in the preceding RNAase H homology domain near the C-terminus. Not all of the individuals in this paper had formal ophthalmological examination
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4814 BUB1 Paul De Fazio gene: BUB1 was added
gene: BUB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: BUB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: BUB1 were set to 35044816; 19772675; 19117986; 23209306
Phenotypes for gene: BUB1 were set to Neurodevelopmental disorder, BUB1-related MONDO:0700092; Intellectual disability and microcephaly
Review for gene: BUB1 was set to GREEN
gene: BUB1 was marked as current diagnostic
Added comment: 2 unrelated patients with ID, microcephaly, short stature, dysmorphic features reported with biallelic variants:

P1 (3yo male): homozygous start-loss variant (2 hets and 0 hom in gnomAD). Functional testing showed a small amount of full-length protein was translated, and BUB1 recruitment to kinetochores was nearly undetectable.
P2 (16yo female): compound heterozygous for a canonical splice variant (1 het and no hom in gnomAD) and an NMD-predicted frameshift variant (absent from gnomAD). The splice variant was shown to result in an in-frame deletion of 54 amino acids in the kinase domain. P2 cells have reduced protein levels but essentially no kinase activity.

BUB1 patient cells have impaired mitotic fidelity.

Homozygous Bub1 disruption in mice is embryonic lethal (PMID:19772675). A hypomorphic mouse is viable with increased tumourigenesis with ageing and aneuploidy (PMID:19117986). A kinase-dead mouse does not show increased tumourigenesis but does have a high frequency of aneuploid cells (PMID:23209306)
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4807 HIST1H4J Zornitza Stark Phenotypes for gene: HIST1H4J were changed from microcephaly; intellectual disability; dysmorphic features to Tessadori-van Haaften neurodevelopmental syndrome 2 , MIM# 619759
Intellectual disability syndromic and non-syndromic v0.4799 PLCH1 Zornitza Stark Phenotypes for gene: PLCH1 were changed from Holoprosencephaly spectrum; Severe developmental delay; Brain malformations to Holoprosencephaly 14, MIM# 619895
Intellectual disability syndromic and non-syndromic v0.4798 PLCH1 Zornitza Stark edited their review of gene: PLCH1: Changed phenotypes: Holoprosencephaly 14, MIM# 619895
Intellectual disability syndromic and non-syndromic v0.4798 SLC38A3 Zornitza Stark Phenotypes for gene: SLC38A3 were changed from developmental epileptic encephalopathy, SLC38A3-related MONDO:0100062 to Developmental and epileptic encephalopathy 102, MIM# 619881
Intellectual disability syndromic and non-syndromic v0.4797 SLC38A3 Zornitza Stark reviewed gene: SLC38A3: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 102, MIM# 619881; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4793 ZNF526 Zornitza Stark Phenotypes for gene: ZNF526 were changed from Intellectual disability; Microcephaly; Cataracts; Epilepsy; Hypertonia; Dystonia to Dentici-Novelli neurodevelopmental syndrome, MIM# 619877
Intellectual disability syndromic and non-syndromic v0.4791 GEMIN4 Chirag Patel reviewed gene: GEMIN4: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 25558065, 30237576, 27878435; Phenotypes: Neurodevelopmental disorder with microcephaly, cataracts, and renal abnormalities, MIM# 617913; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4787 CPSF3 Zornitza Stark Phenotypes for gene: CPSF3 were changed from Neurodevelopmental disorder, CPSF3-related, MONDO:0700092 to Neurodevelopmental disorder with microcephaly, hypotonia, and seizures (NEDMHS), MIM#619876
Intellectual disability syndromic and non-syndromic v0.4786 CPSF3 Zornitza Stark reviewed gene: CPSF3: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, hypotonia, and seizures (NEDMHS), MIM#619876; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4786 MFF Zornitza Stark Phenotypes for gene: MFF were changed from to Encephalopathy due to defective mitochondrial and peroxisomal fission 2, MIM# 617086
Intellectual disability syndromic and non-syndromic v0.4783 MFF Zornitza Stark reviewed gene: MFF: Rating: GREEN; Mode of pathogenicity: None; Publications: 22499341, 26783368, 32181496; Phenotypes: Encephalopathy due to defective mitochondrial and peroxisomal fission 2, MIM# 617086; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4766 RHEB Zornitza Stark Phenotypes for gene: RHEB were changed from Intellectual disability; Macrocephaly; Focal cortical dysplasia to Neurodevelopmental disorder MONDO:0700092, RHEB-related; Intellectual disability; Macrocephaly; Focal cortical dysplasia
Intellectual disability syndromic and non-syndromic v0.4765 RHEB Zornitza Stark edited their review of gene: RHEB: Changed phenotypes: Neurodevelopmental disorder MONDO:0700092, RHEB-related, Intellectual disability, Macrocephaly, Focal cortical dysplasia
Intellectual disability syndromic and non-syndromic v0.4755 ACTL6B Zornitza Stark edited their review of gene: ACTL6B: Changed phenotypes: Epileptic encephalopathy, early infantile, 76, MIM# 618468, Intellectual developmental disorder with severe speech and ambulation defects, MIM# 618470; Changed mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4741 DNAH14 Chern Lim gene: DNAH14 was added
gene: DNAH14 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: DNAH14 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DNAH14 were set to PMID: 35438214
Phenotypes for gene: DNAH14 were set to Neurodevelopmental disorder, DNAH14-related (MONDO#0700092)
Review for gene: DNAH14 was set to GREEN
gene: DNAH14 was marked as current diagnostic
Added comment: PMID: 35438214:
- Three previously unreported patients with compound heterozygous DNAH14 variants, including one nonsense, one frameshift, and four missense variants. A spectrum of neurological and developmental phenotypes was observed, including seizures, global developmental delay, microcephaly, and hypotonia.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4740 DROSHA Lucy Spencer gene: DROSHA was added
gene: DROSHA was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: DROSHA was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: DROSHA were set to 35405010
Phenotypes for gene: DROSHA were set to Neurodevelopmental disorder (MONDO#0700092), DROSHA-related
Review for gene: DROSHA was set to AMBER
Added comment: 2 individuals with profound intellectual disability, epilepsy, white matter atrophy, microcephaly, and dysmorphic features, who carry damaging de novo heterozygous variants in DROSHA. Both variants are missense, absent from gnomad. Both individuals noted to have Rett-like features.

Functional studies in patient fibroblasts showed one of the missense altered the expression of mature miRNA. Fruit fly models with homozygous LOF variants die during larval stages. introduction of the missense seen in the patients was able to partially rescue this phenotype suggesting LOF is not the mechanism.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4739 DTYMK Zornitza Stark Phenotypes for gene: DTYMK were changed from Intellectual disability; microcephaly to Neurodegeneration, childhood-onset, with progressive microcephaly (MIM# 619847)
Intellectual disability syndromic and non-syndromic v0.4732 PPFIBP1 Zornitza Stark gene: PPFIBP1 was added
gene: PPFIBP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: PPFIBP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PPFIBP1 were set to https://www.medrxiv.org/content/10.1101/2022.04.04.22273309v1
Phenotypes for gene: PPFIBP1 were set to Neurodevelopmental disorder, MONDO:0700092, PPFIBP1-related
Review for gene: PPFIBP1 was set to GREEN
Added comment: 16 individuals from 10 unrelated families reported with moderate to profound developmental delay, often refractory early-onset epilepsy and progressive microcephaly. Drosophila model.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.4731 DTYMK Daniel Flanagan reviewed gene: DTYMK: Rating: GREEN; Mode of pathogenicity: None; Publications: 34918187; Phenotypes: Neurodegeneration, childhood-onset, with progressive microcephaly (MIM# 619847); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4724 SIK1 Zornitza Stark Phenotypes for gene: SIK1 were changed from to Developmental and epileptic encephalopathy 30, MIM#616341; developmental and epileptic encephalopathy, MONDO#0100062
Intellectual disability syndromic and non-syndromic v0.4721 SIK1 Zornitza Stark reviewed gene: SIK1: Rating: GREEN; Mode of pathogenicity: None; Publications: 25839329, 27966542, 35267137; Phenotypes: Developmental and epileptic encephalopathy 30, MIM#616341, developmental and epileptic encephalopathy, MONDO#0100062; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4720 HERC1 Zornitza Stark Phenotypes for gene: HERC1 were changed from to Macrocephaly, dysmorphic facies, and psychomotor retardation, MIM# 617011
Intellectual disability syndromic and non-syndromic v0.4717 HERC1 Zornitza Stark reviewed gene: HERC1: Rating: GREEN; Mode of pathogenicity: None; Publications: 28323226, 27108999, 26153217, 26138117, 20041218; Phenotypes: Macrocephaly, dysmorphic facies, and psychomotor retardation, MIM# 617011; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4713 HCN1 Zornitza Stark Phenotypes for gene: HCN1 were changed from to Developmental and epileptic encephalopathy 24, MIM# 615871; Generalized epilepsy with febrile seizures plus, type 10, MIM# 618482
Intellectual disability syndromic and non-syndromic v0.4710 HCN1 Zornitza Stark reviewed gene: HCN1: Rating: GREEN; Mode of pathogenicity: None; Publications: 24747641, 30351409, 30351409; Phenotypes: Developmental and epileptic encephalopathy 24, MIM# 615871, Generalized epilepsy with febrile seizures plus, type 10, MIM# 618482; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4698 CIT Zornitza Stark Phenotypes for gene: CIT were changed from to Microcephaly 17, primary, autosomal recessive (MIM#617090)
Intellectual disability syndromic and non-syndromic v0.4695 CIT Zornitza Stark reviewed gene: CIT: Rating: GREEN; Mode of pathogenicity: None; Publications: 27453578, 27503289, 27453579; Phenotypes: Microcephaly 17, primary, autosomal recessive (MIM#617090); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4690 PIDD1 Zornitza Stark Phenotypes for gene: PIDD1 were changed from Global developmental delay; Intellectual disability; Seizures; Autism; Behavioral abnormality; Psychosis; Pachygyria; Lissencephaly; Abnormality of the corpus callosum to Intellectual developmental disorder, autosomal recessive 75, with neuropsychiatric features and variant lissencephaly, MIM# 619827
Intellectual disability syndromic and non-syndromic v0.4689 PIDD1 Zornitza Stark reviewed gene: PIDD1: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Intellectual developmental disorder, autosomal recessive 75, with neuropsychiatric features and variant lissencephaly, MIM# 619827; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4684 FASTKD2 Bryony Thompson reviewed gene: FASTKD2: Rating: GREEN; Mode of pathogenicity: None; Publications: 18771761, 28499982, 31944455, 34234304; Phenotypes: FASTKD2-related infantile mitochondrial encephalomyopathy MONDO:0015632; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4684 PPP1R15B Zornitza Stark Phenotypes for gene: PPP1R15B were changed from to Microcephaly, short stature, and impaired glucose metabolism 2, MIM# 616817
Intellectual disability syndromic and non-syndromic v0.4680 PPP1R15B Zornitza Stark reviewed gene: PPP1R15B: Rating: AMBER; Mode of pathogenicity: None; Publications: 26159176, 26307080, 27640355; Phenotypes: Microcephaly, short stature, and impaired glucose metabolism 2, MIM# 616817; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4661 CACNA2D1 Alison Yeung Phenotypes for gene: CACNA2D1 were changed from developmental and epileptic encephalopathy disorder MONDO:0100062 CACNA2D1-related to Developmental and epileptic encephalopathy disorder MONDO:0100062 CACNA2D1-related
Intellectual disability syndromic and non-syndromic v0.4658 CACNA2D1 Michelle Torres gene: CACNA2D1 was added
gene: CACNA2D1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CACNA2D1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CACNA2D1 were set to 35293990
Phenotypes for gene: CACNA2D1 were set to developmental and epileptic encephalopathy disorder MONDO:0100062 CACNA2D1-related
Review for gene: CACNA2D1 was set to GREEN
Added comment: PMID 35293990: WES of 2x unrelated individuals with early-onset developmental epileptic encephalopathy, microcephaly, severe hypotonia, absent speech, spasticity, choreiform movements, orofacial dyskinesia, and 2 cortical visual impairment, corpus callosum hypoplasia and progressive volume loss. Patient 2 also had a tiny patent foramen ovale.

Patient 1 is homozygous for p.(Ser275Asnfs*13). mRNA and protein expression were reduced to ~10% of WT in fibroblasts

Patient 2 is cHet for p.(Leu9Alafs*5) and p.(Gly209Asp). mRNA expression in patients fibroblasts was similar to controls, and protein expression reduced to 31-38%. Functional of the p.(Gly209Asp) showed impaired localization and mutagenesis showed complete loss of channel function.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4658 TRAPPC10 Naomi Baker gene: TRAPPC10 was added
gene: TRAPPC10 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TRAPPC10 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TRAPPC10 were set to PMID: 35298461; 30167849
Phenotypes for gene: TRAPPC10 were set to neurodevelopmental disorder (MONDO:0700092), TRAPPC10-related
Review for gene: TRAPPC10 was set to GREEN
Added comment: PMID: 35298461 – two Pakistani families reported with homozygous variants. Family 1 has frameshift variant in 8 affected individual and family 2 has missense variant in 2 affected individuals. Patients present with microcephaly, short stature, hypotonia, severe ID and behavioural abnormalities. Seizures also reported in 4/10 individuals. Paper also reported brain abnormalities in null mouse model and other functional in transfected cell lines.

PMID: 30167849 – initial report of family 2 above.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4658 ADAM22 Alison Yeung Phenotypes for gene: ADAM22 were changed from Epileptic encephalopathy, early infantile, 61, MIM# 617933 to Developmental and epileptic encephalopathy 61 (MIM#617933)
Intellectual disability syndromic and non-syndromic v0.4656 ADAM22 Lucy Spencer reviewed gene: ADAM22: Rating: GREEN; Mode of pathogenicity: None; Publications: 35373813; Phenotypes: Developmental and epileptic encephalopathy 61 (MIM#617933); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4656 AHSG Elena Savva gene: AHSG was added
gene: AHSG was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: AHSG was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: AHSG were set to PMID: 28054173; 9395485; 31288248; 17389622
Phenotypes for gene: AHSG were set to ?Alopecia-intellectual disability syndrome 1 MIM#203650; infantile cortical hyperostosis
Review for gene: AHSG was set to RED
Added comment: PMID: 28054173 - 7 relatives within a large consanguinous fam w/ alopecia and ID, and a hom missense (p.Arg317His). Modelling predicts this variant to be a phosphorylation site, functional studies show a difference in protein size. Unclear biological significance.
Alt change with stronger GS (p.(Arg317Cys)) is a common poly with 19 homozygotes in gnomAD.

No hom PTCs in gnomAD

PMID: 9395485 - K/O mouse model shows no gross anatomical abnormalities, were fertile and "healthy". No mentioned of ID, alopecia
PMID: 17389622 - K/O mouse model on the calcification resistant genetic background C57BL/6, shows uraemia and phosphate challenge. No mentioned of ID, alopecia

PMID: 31288248 - 1 hom infant (p.K2*, within 5' NMD escape region) with infantile cortical hyperostosis, loss of enzyme in patient serum shown by ELISA. No mentioned of ID, alopecia
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4640 WDR11 Elena Savva Phenotypes for gene: WDR11 were changed from Intellectual disability; Microcephaly; Short stature to Neurodevelopmental disorder, MONDO:0700092, WDR11-related
Intellectual disability syndromic and non-syndromic v0.4612 GRIN1 Zornitza Stark Phenotypes for gene: GRIN1 were changed from Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal dominant, MIM# 614254; Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal recessive, MIM# 617820 to Developmental and epileptic encephalopathy 101 , MIM#619814; Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal dominant, MIM# 614254; Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal recessive, MIM# 617820
Intellectual disability syndromic and non-syndromic v0.4610 GRIN1 Zornitza Stark edited their review of gene: GRIN1: Changed publications: 29365063, 27164704, 27164704, 28051072, 34611970; Changed phenotypes: Developmental and epileptic encephalopathy 101 , MIM#619814, Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal dominant, MIM# 614254, Neurodevelopmental disorder with or without hyperkinetic movements and seizures, autosomal recessive, MIM# 617820
Intellectual disability syndromic and non-syndromic v0.4580 NDUFV2 Zornitza Stark changed review comment from: Multiple unrelated families. Common presenting features include HOCM and encephalopathy, unclear in what proportion ID is likely to be the presenting or main feature.; to: Multiple unrelated families. Common presenting features include HOCM and encephalopathy, or episodic regression with cavitating leukoencephalopathy, unclear in what proportion ID is likely to be the presenting or main feature.
Intellectual disability syndromic and non-syndromic v0.4580 SYNJ1 Zornitza Stark Phenotypes for gene: SYNJ1 were changed from to Developmental and epileptic encephalopathy 53, MIM# 617389
Intellectual disability syndromic and non-syndromic v0.4577 SYNJ1 Zornitza Stark reviewed gene: SYNJ1: Rating: GREEN; Mode of pathogenicity: None; Publications: 32435303, 27435091; Phenotypes: Developmental and epileptic encephalopathy 53, MIM# 617389; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4575 SZT2 Zornitza Stark reviewed gene: SZT2: Rating: GREEN; Mode of pathogenicity: None; Publications: 23932106, 30560016, 30359774, 28556953, 32402703; Phenotypes: Developmental and epileptic encephalopathy 18, OMIM #615476; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4571 ITPA Zornitza Stark Phenotypes for gene: ITPA were changed from to Developmental and epileptic encephalopathy 35, MIM# 616647
Intellectual disability syndromic and non-syndromic v0.4568 ITPA Zornitza Stark reviewed gene: ITPA: Rating: GREEN; Mode of pathogenicity: None; Publications: 26224535, 19498443, 35234647, 35098521; Phenotypes: Developmental and epileptic encephalopathy 35, MIM# 616647; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4547 FBXO28 Zornitza Stark Phenotypes for gene: FBXO28 were changed from Developmental and epileptic encephalopathy to Developmental and epileptic encephalopathy 100, MIM# 619777
Intellectual disability syndromic and non-syndromic v0.4546 FBXO28 Zornitza Stark edited their review of gene: FBXO28: Changed phenotypes: Developmental and epileptic encephalopathy 100, MIM# 619777
Intellectual disability syndromic and non-syndromic v0.4546 NAT8L Krithika Murali gene: NAT8L was added
gene: NAT8L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NAT8L was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NAT8L were set to 11310630; 19807691; 32275776
Phenotypes for gene: NAT8L were set to ?N-acetylaspartate deficiency - MIM#614063
Review for gene: NAT8L was set to AMBER
Added comment: Absence of brain N-acetylaspartate, has been described in only one patient, with truncal ataxia, marked developmental delay, seizures and secondary microcephaly (first described by - PMID: 11310630 Martin et al 2001). PMID: 19807691 - Wiame et al 2009 identified in this patient a homozygous 19 bp NAT8L gene deletion, resulting in a change in reading frame and the absence of production of a functional protein. The affected individual is adopted and testing of the biological parents was not possible. The authors provide supportive functional studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4524 HIST1H4D Paul De Fazio changed review comment from: Single individual described with a de novo missense variant Arg41His (Arg40 in H4 nomenclature). Apart from langauge delay and moderate ID, phenotypes included facial dysmorphisms and cochlear abnormalities and arhinencephaly on MRI. Hearing was normal. Birth length, OFC, weight were all reduced (-2 to -2.5SD).
A zebrafish model has developmental defects.
Sources: Literature; to: HGNC recognised gene name: H4C4
Single individual described with a de novo missense variant Arg41His (Arg40 in H4 nomenclature). Apart from langauge delay and moderate ID, phenotypes included facial dysmorphisms and cochlear abnormalities and arhinencephaly on MRI. Hearing was normal. Birth length, OFC, weight were all reduced (-2 to -2.5SD).
A zebrafish model has developmental defects.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4521 HIST1H4C Zornitza Stark Phenotypes for gene: HIST1H4C were changed from Growth delay, microcephaly and intellectual disability to Tessadori-van Haaften neurodevelopmental syndrome 1 MIM#619758
Intellectual disability syndromic and non-syndromic v0.4520 CPSF3 Belinda Chong gene: CPSF3 was added
gene: CPSF3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CPSF3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CPSF3 were set to 35121750
Phenotypes for gene: CPSF3 were set to Intellectual disability syndrome
Review for gene: CPSF3 was set to GREEN
gene: CPSF3 was marked as current diagnostic
Added comment: Study of a deficit of observed homozygous carriers of missense variants, versus an expected number in a set of 153,054 chip-genotyped Icelanders, to identify potentially pathogenic genotypes

Six homozygous carriers of missense variants in CPSF3 show severe intellectual disability, seizures, microcephaly, and abnormal muscle tone.

- Four identified through Icelandic geneology (p.Gly468Glu), three carrier couples total of four children who had died prematurely. Tested archival samples for two of these children, and confirm a homozygous genotype.
- Two of Mexican descent (p.Ile354Thr), first-degree cousins
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4519 NRCAM Ee Ming Wong gene: NRCAM was added
gene: NRCAM was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NRCAM was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NRCAM were set to PMID: 35108495
Phenotypes for gene: NRCAM were set to neurodevelopmental disorder, MONDO:0700092
Penetrance for gene: NRCAM were set to unknown
Review for gene: NRCAM was set to GREEN
gene: NRCAM was marked as current diagnostic
Added comment: -Ten individuals from 8 families with developmental delay/intellectual disability, hypotonia, peripheral neuropathy, and/or spasticity
- Affected individuals are biallelic for missense and/or LoF variants which are mainly in the fibronectin type III (Fn-III) domain
- Zebrafish mutants lacking the third Fn-III domain displayed significantly altered swimming behavior compared to wild-type larvae (p < 0.03) and a trend toward increased amounts of alpha-tubulin fibers in the dorsal telencephalon, demonstrating an alteration in white matter tracts and projections
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4519 HIST1H4D Paul De Fazio gene: HIST1H4D was added
gene: HIST1H4D was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HIST1H4D was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: HIST1H4D were set to 35202563
Phenotypes for gene: HIST1H4D were set to Neurodevelopmental disorder, HIST1H4D-related MONDO:0700092
Review for gene: HIST1H4D was set to AMBER
gene: HIST1H4D was marked as current diagnostic
Added comment: Single individual described with a de novo missense variant Arg41His (Arg40 in H4 nomenclature). Apart from langauge delay and moderate ID, phenotypes included facial dysmorphisms and cochlear abnormalities and arhinencephaly on MRI. Hearing was normal. Birth length, OFC, weight were all reduced (-2 to -2.5SD).
A zebrafish model has developmental defects.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4519 CRLS1 Michelle Torres gene: CRLS1 was added
gene: CRLS1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CRLS1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CRLS1 were set to 35147173
Phenotypes for gene: CRLS1 were set to Mitochondrial disease MONDO:0044970 CRLS1-related
Added comment: - Three families (4 individuals) with cardiolipin deficiency.
- Two families (one consanguineous with 2 affected siblings) with homozygous the p.(Ile109Asn) had infantile progressive encephalopathy, bull’s eye maculopathy, auditory neuropathy, diabetes insipidus, autonomic instability, cardiac defects and early death.
- The fourth individual cHet p.(Ala172Asp) and p.(Leu217Phe) presented with chronic encephalopathy with neurodevelopmental regression, congenital nystagmus with decreased vision, sensorineural hearing loss, failure to thrive and acquired microcephaly.
- Functional studies on patient cells showed increased levels of the substrate of CRLS1 and impaired mitochondrial morphology and biogenesis
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4519 ZBTB7A Daniel Flanagan gene: ZBTB7A was added
gene: ZBTB7A was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: ZBTB7A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ZBTB7A were set to 34515416; 31645653
Phenotypes for gene: ZBTB7A were set to Macrocephaly, neurodevelopmental delay, lymphoid hyperplasia, and persistent fetal hemoglobin (MIM#619769)
Review for gene: ZBTB7A was set to GREEN
Added comment: PMID: 34515416. Monoallelic ZBTB7A variants identified in 12 individuals from 11 families, with macrocephaly (11/12), some degree of ID (12/12), autistic features (7/12) and hypertrophy of pharyngeal lymphoid tissue (12/12). Variants included LoF variants and missense, 8 variants were de novo.

PMID: 31645653. De novo ZBTB7A missense identified in a boy with macrocephaly, intellectual disability, and sleep apnea.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.4510 ATP6V0A1 Chern Lim reviewed gene: ATP6V0A1: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID:34909687; Phenotypes: Early-onset progressive myoclonus epilepsy with ataxia, AR, severe developmental and epileptic encephalopathy, AD.; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.4510 HIST1H4J Elena Savva reviewed gene: HIST1H4J: Rating: AMBER; Mode of pathogenicity: None; Publications: PMID: 35202563, 31804630; Phenotypes: Neurodevelopmental syndrome, microcephaly, intellectual disability, dysmorphic features; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability syndromic and non-syndromic v0.4509 CHKA Zornitza Stark Phenotypes for gene: CHKA were changed from Abnormal muscle tone; Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormality of movement; Abnormality of nervous system morphology; Short stature to Neurodevelopmental disorder, MONDO:0700092; Abnormal muscle tone; Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormality of movement; Abnormality of nervous system morphology; Short stature
Intellectual disability syndromic and non-syndromic v0.4507 CHKA Konstantinos Varvagiannis gene: CHKA was added
gene: CHKA was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CHKA was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CHKA were set to 35202461
Phenotypes for gene: CHKA were set to Abnormal muscle tone; Global developmental delay; Intellectual disability; Seizures; Microcephaly; Abnormality of movement; Abnormality of nervous system morphology; Short stature
Penetrance for gene: CHKA were set to Complete
Review for gene: CHKA was set to GREEN
Added comment: Klöckner (2022 - PMID: 35202461) describe the phenotype of 6 individuals (from 5 unrelated families) harboring biallelic CHKA variants.

Shared features incl. abnormal muscle tone(6/6 - hypertonia or hypotonia, 3/6 each), DD/ID (6/6,severe in 4, severe/profound in 2), epilepsy (6/6 - onset: infancy - 3y2m | epileptic spasms or GS at onset), microcephaly (6/6), movement disorders (3/6 - incl. dyskinesia, rigidity, choreoatetotic movements). 2/5 individuals exhibited MRI abnormalities, notably hypomyelination. Short stature was observed in 4/6.

Eventual previous genetic testing was not discussed.

Exome sequencing (quattro ES for 2 sibs, trio ES for 1 individual, singleton for 3 probands) revealed biallelic CHKA variants in all affected individuals. Sanger sequencing was performed for confirmation and segregation studies.

Other variants (in suppl.) were not deemed to be causative for the neurodevelopmental phenotype.

3 different missense, 1 start-loss and 1 truncating variant were identified, namely (NM_0012772.2):
- c.421C>T/p.(Arg141Trp) [3 hmz subjects from 2 consanguineous families],
- c.580C>T/p.Pro194Ser [1 hmz individual born to consanguineous parents],
- c.2T>C/p.(Met1?) [1 hmz individual born to related parents],
- c.14dup/p.(Cys6Leufs*19) in trans with c.1021T>C/p.(Phe341Leu) in 1 individual.

CHKA encodes choline kinase alpha, an enzyme catalyzing the first step of phospholipid synthesis in the Kennedy pathway. The pathway is involved in de novo synthesis of glycerophospholipids, phosphatidylcholine and phosphatidylethanolamine being the most abundant in eukaryotic membranes.

CHKA with its paralog (CHKB) phosphorylates either choline or ethanolamine to phosphocholine or phosphoethanolamine respectively with conversion of ATP to ADP.

As the authors comment, biallelic pathogenic variants in CHKB cause a NDD with muscular dystrophy, hypotonia, ID, microcephaly and structural mitochondrial anomalies (MIM 602541). [Prominent mitochondrial patterning was observed in a single muscle biopsy available from an individual with biallelic CHKA variants].

Other disorders of the Kennedy pathway (due to biallelic PCYT2, SELENOI, PCYT1A variants) present with overlapping features incl. variable DD/ID (no-severe), microcephaly, seizures, visual impairment etc.

CHKA variants were either absent or observed once in gnomAD, affected highly conserved AAs with multiple in silico predictions in favor of a deleterious effect.

In silico modeling suggests structural effects for several of the missense variants (Arg141Trp, Pro194Ser presumably affect ADP binding, Phe341 lying close to the binding site of phosphocholine).

Each of the missense variants was expressed in yeast cells and W. Blot suggested expression at the expected molecular weight at comparative levels. The 3 aforementioned variants exhibited reduced catalytic activity (20%, 15%, 50% respectively).

NMD is thought to underly the deleterious effect of the frameshift one (not studied).

The start-loss variant is expected to result in significantly impaired expression and protein function as eventual utilization of the next possible start codon - occurring at position 123 - would remove 26% of the protein.

Chka(-/-) is embryonically lethal in mice, suggesting that complete loss is not compatible with life. Reduction of choline kinase activity by 30% in heterozygous mice did not appear to result in behavioral abnormalities although this was not studied in detail (PMID cited: 18029352). Finally, screening of 1566 mouse lines identified 198 genes whose disruption yields neuroanatomical phenotypes, Chka(+/-) mice being among these (PMID cited: 31371714).

There is no associated phenotype in OMIM, Gene2Phenotype or SysID.

Overall this gene can be considered for inclusion in the ID and epilepsy panes with green or amber rating (>3 individuals, >3 variants, variant studies, overlapping phenotype of disorders belonging to the same pathway, etc). Consider also inclusion in the microcephaly panel (where available this seemed to be of postnatal onset).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4495 THUMPD1 Chern Lim changed review comment from: Broly, M. et al. (2022), AJHG:
- 13 individuals from 8 families, loss of function variants (PTVs, one missense, one single AA del).
- Common phenotypic findings included global developmental delay, speech delay, moderate to severe intellectual deficiency, behavioral abnormalities such as angry outbursts, facial dysmorphism and ophthalmological abnormalities.
Sources: Other; to: Broly, M. et al. (2022), AJHG:
- 13 individuals from 8 families, biallelic loss of function variants (PTVs, one missense, one single AA del).
- Common phenotypic findings included global developmental delay, speech delay, moderate to severe intellectual deficiency, behavioral abnormalities such as angry outbursts, facial dysmorphism and ophthalmological abnormalities.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.4495 THUMPD1 Chern Lim changed review comment from: Broly, M. et al. (2022) manuscript accepted in AJHG:
- 13 individuals from 8 families, loss of function variants (PTVs, one missense, one single AA del).
- Common phenotypic findings included global developmental delay, speech delay, moderate to severe intellectual deficiency, behavioral abnormalities such as angry outbursts, facial dysmorphism and ophthalmological abnormalities.
Sources: Other; to: Broly, M. et al. (2022), AJHG:
- 13 individuals from 8 families, loss of function variants (PTVs, one missense, one single AA del).
- Common phenotypic findings included global developmental delay, speech delay, moderate to severe intellectual deficiency, behavioral abnormalities such as angry outbursts, facial dysmorphism and ophthalmological abnormalities.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.4495 THUMPD1 Chern Lim gene: THUMPD1 was added
gene: THUMPD1 was added to Intellectual disability syndromic and non-syndromic. Sources: Other
Mode of inheritance for gene: THUMPD1 was set to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: THUMPD1 were set to Syndromic form of intellectual disability associated with developmental delay, behavioral abnormalities, hearing loss and facial dysmorphism, AR
gene: THUMPD1 was marked as current diagnostic
Added comment: Broly, M. et al. (2022) manuscript accepted in AJHG:
- 13 individuals from 8 families, loss of function variants (PTVs, one missense, one single AA del).
- Common phenotypic findings included global developmental delay, speech delay, moderate to severe intellectual deficiency, behavioral abnormalities such as angry outbursts, facial dysmorphism and ophthalmological abnormalities.
Sources: Other
Intellectual disability syndromic and non-syndromic v0.4485 BAP1 Anna Ritchie gene: BAP1 was added
gene: BAP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: BAP1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: BAP1 were set to PMID: 35051358
Phenotypes for gene: BAP1 were set to syndromic intellectual disability MONDO:0000508
Penetrance for gene: BAP1 were set to unknown
Review for gene: BAP1 was set to GREEN
Added comment: 11 de novo germline heterozygous missense BAP1 variants associated with a rare syndromic neurodevelopmental disorder. Functional analysis showed that most of the variants cannot rescue the consequences of BAP1 inactivation, suggesting a loss-of-function mechanism. All affected individuals harboring a de novo BAP1 variant had DD or ID (11/11) characterized notably by speech (11/ 11) and motor delay (6/11). Most of them had hypotonia (7/11), seizures (6/11), and abnormal behavior (8/10), including autism spectrum disorder, attention deficit hyperactivity disorder, and hypersensitivity. Almost all individuals showed dysmorphic facial features (10/11), and more than half (6/11) had skeletal malformations (involving the hands [4/11], feet [3/11], or spine [2/11]). Most of the individuals had growth failure (9/11), including four individuals with a very short stature.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4482 MAN2C1 Michelle Torres gene: MAN2C1 was added
gene: MAN2C1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MAN2C1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MAN2C1 were set to 35045343
Phenotypes for gene: MAN2C1 were set to neurodevelopmental disorder MONDO:0700092 MAN2C1-related
Review for gene: MAN2C1 was set to GREEN
Added comment: Six individuals from four different families, including two fetuses, exhibiting dysmorphic facial features, congenital anomalies such as tongue hamartoma, variable degrees of intellectual disability, and brain anomalies including polymicrogyria, interhemispheric cysts, hypothalamic hamartoma, callosal anomalies, and hypoplasia of brainstem and cerebellar vermis. Variants include PTC and missense.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4482 SLC38A3 Ain Roesley gene: SLC38A3 was added
gene: SLC38A3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SLC38A3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLC38A3 were set to 34605855
Phenotypes for gene: SLC38A3 were set to developmental epileptic encephalopathy, SLC38A3-related MONDO:0100062
Penetrance for gene: SLC38A3 were set to Complete
Review for gene: SLC38A3 was set to GREEN
gene: SLC38A3 was marked as current diagnostic
Added comment: 7 families 6 of whom are consanguineous but unique variants in all of them

10/10 with GDD/ID
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4481 FRA10AC1 Zornitza Stark gene: FRA10AC1 was added
gene: FRA10AC1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FRA10AC1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FRA10AC1 were set to 34694367
Phenotypes for gene: FRA10AC1 were set to Neurodevelopmental disorder, MONDO:0700092, FRA10AC1-related
Review for gene: FRA10AC1 was set to GREEN
Added comment: PMID 34694367: 5 individuals from 3 unrelated families reported.

Variable ID, possibly related to variant type with LoF variants associated with more severe ID. All individuals had microcephaly, hypoplasia or agenesis of the corpus callosum, growth retardation, and craniofacial dysmorphism.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4480 PLAA Zornitza Stark Phenotypes for gene: PLAA were changed from to Neurodevelopmental disorder with progressive microcephaly, spasticity, and brain anomalies, MIM# 617527
Intellectual disability syndromic and non-syndromic v0.4477 PLAA Zornitza Stark reviewed gene: PLAA: Rating: GREEN; Mode of pathogenicity: None; Publications: 28007986, 28413018, 31322726; Phenotypes: Neurodevelopmental disorder with progressive microcephaly, spasticity, and brain anomalies, MIM# 617527; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4472 NAA20 Zornitza Stark Phenotypes for gene: NAA20 were changed from Autosomal recessive developmental delay, intellectual disability, and microcephaly to Intellectual developmental disorder, autosomal recessive 73, MIM# 619717
Intellectual disability syndromic and non-syndromic v0.4454 MDH2 Zornitza Stark Phenotypes for gene: MDH2 were changed from to Developmental and epileptic encephalopathy 51 MIM#617339
Intellectual disability syndromic and non-syndromic v0.4451 MDH2 Zornitza Stark reviewed gene: MDH2: Rating: GREEN; Mode of pathogenicity: None; Publications: 27989324, 34766628; Phenotypes: Developmental and epileptic encephalopathy 51 MIM#617339; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4441 LMBRD2 Zornitza Stark Phenotypes for gene: LMBRD2 were changed from Global developmental delay; Intellectual disability; Microcephaly; Seizures; Abnormality of nervous system morphology; Abnormality of the eye to Developmental delay with variable neurologic and brain abnormalities, MIM# 619694; Global developmental delay; Intellectual disability; Microcephaly; Seizures; Abnormality of nervous system morphology; Abnormality of the eye
Intellectual disability syndromic and non-syndromic v0.4438 ANAPC7 Zornitza Stark gene: ANAPC7 was added
gene: ANAPC7 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ANAPC7 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ANAPC7 were set to 34942119
Phenotypes for gene: ANAPC7 were set to Ferguson-Bonni neurodevelopmental syndrome, MIM# 619699
Review for gene: ANAPC7 was set to AMBER
Added comment: 11 individuals of Amish heritage reported homozygous for an intragenic deletion. Clinical features included ID, hypotonia, deafness in 5, relatively small head size (but microcephaly only in 1), and occasional congenital anomalies.

Supportive mouse model.

Amber rating in light of this being a founder variant.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4437 DISP1 Zornitza Stark Phenotypes for gene: DISP1 were changed from Holoprosencephaly to Holoprosencephaly, MONDO:0016296
Intellectual disability syndromic and non-syndromic v0.4435 SIN3A Chirag Patel changed review comment from: 9 patients from 5 unrelated families reported with heterozygous truncating mutations in the SIN3A gene. Features include intellectual disability, ASD, seizures, dysmorphism, short stature, microcephaly, joint hypermotility, and small hands and feet. Brain imaging showed dilated ventricles, thin corpus callosum and, in some cases, dysgyria or polymicrogyria. Suitable for fetal anomalies panel.; to: 9 patients from 5 unrelated families reported with heterozygous truncating mutations in the SIN3A gene. Features include intellectual disability, ASD, seizures, dysmorphism, short stature, microcephaly, joint hypermotility, and small hands and feet. Brain imaging showed dilated ventricles, thin corpus callosum and, in some cases, dysgyria or polymicrogyria.
Intellectual disability syndromic and non-syndromic v0.4433 NSD2 Zornitza Stark Phenotypes for gene: NSD2 were changed from Microcephaly; intellectual disability to Rauch-Steindl syndrome, MIM# 619695; Microcephaly; intellectual disability
Intellectual disability syndromic and non-syndromic v0.4432 NSD2 Zornitza Stark edited their review of gene: NSD2: Changed phenotypes: Rauch-Steindl syndrome, MIM# 619695, Microcephaly, intellectual disability
Intellectual disability syndromic and non-syndromic v0.4426 NAA10 Zornitza Stark Phenotypes for gene: NAA10 were changed from to Microphthalmia, syndromic 1, MIM# 309800; Ogden syndrome MIM#300855
Intellectual disability syndromic and non-syndromic v0.4423 NAA10 Zornitza Stark reviewed gene: NAA10: Rating: GREEN; Mode of pathogenicity: None; Publications: 30842225, 34075687, 21700266; Phenotypes: Microphthalmia, syndromic 1, MIM# 309800, Ogden syndrome MIM#300855; Mode of inheritance: X-LINKED: hemizygous mutation in males, biallelic mutations in females
Intellectual disability syndromic and non-syndromic v0.4422 VPS50 Zornitza Stark Phenotypes for gene: VPS50 were changed from Neonatal cholestatic liver disease; Failure to thrive; Profound global developmental delay; Postnatal microcephaly; Seizures; Abnormality of the corpus callosum to Neurodevelopmental disorder with microcephaly, seizures, and neonatal cholestasis , MIM#619685; Neonatal cholestatic liver disease; Failure to thrive; Profound global developmental delay; Postnatal microcephaly; Seizures; Abnormality of the corpus callosum
Intellectual disability syndromic and non-syndromic v0.4421 VPS50 Zornitza Stark reviewed gene: VPS50: Rating: AMBER; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, seizures, and neonatal cholestasis , MIM#619685; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4420 CCND2 Alison Yeung Added comment: Comment on phenotypes: Distal variants associated with Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 3

Proximal variants associated with reciprocal phenotype of mild neurodevelopment disorder with microcephaly and short stature
Intellectual disability syndromic and non-syndromic v0.4420 CCND2 Alison Yeung Phenotypes for gene: CCND2 were changed from to Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 3, MIM# 615938; Neurodevelopmental disorder, CCND2-related MONDO: 0700092; Microcephaly, MONDO: 0001149
Intellectual disability syndromic and non-syndromic v0.4416 PRDM13 Seb Lunke gene: PRDM13 was added
gene: PRDM13 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
founder tags were added to gene: PRDM13.
Mode of inheritance for gene: PRDM13 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PRDM13 were set to 34730112
Phenotypes for gene: PRDM13 were set to intellectual disability, MONDO:0001071, PRDM13-associated; ataxia with cerebellar hypoplasia
Review for gene: PRDM13 was set to AMBER
Added comment: Recessive disease causing ID and DSD described in three supposedly unrelated families (2 consanguine), but all are from Malta, and all share the same 13bp deletion spanning an exon-intron boundary. Mouse KO is embryonically lethal, and tissue specific KO failed to replicate many of the patients phenotypes, other than hypoplasia of the cerebellar vermis and hemispheres at P21.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4415 NAA20 Zornitza Stark reviewed gene: NAA20: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Autosomal recessive developmental delay, intellectual disability, and microcephaly; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4408 NAA20 Chirag Patel gene: NAA20 was added
gene: NAA20 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NAA20 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NAA20 were set to PMID: 34230638
Phenotypes for gene: NAA20 were set to Autosomal recessive developmental delay, intellectual disability, and microcephaly
Added comment: 2 consanguineous families with 5 affected individuals with developmental delay, intellectual disability, and microcephaly (-2-4SD). Exome and genome sequencing identified 2 different homozygous variants in NAA20 gene (p.Met54Val and p.Ala80Val), and segregated with affected individuals. N-terminal acetyltransferases modify proteins by adding an acetyl moiety to the first amino acid and are vital for protein and cell function. The NatB complex acetylates 20% of the human proteome and is composed of the catalytic subunit NAA20 and the auxiliary subunit NAA25. Both NAA20-M54V and NAA20-A80V were impaired in their capacity to form a NatB complex with NAA25, and in vitro acetylation assays revealed reduced catalytic activities toward different NatB substrates.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4390 FLVCR2 Zornitza Stark Phenotypes for gene: FLVCR2 were changed from to Proliferative vasculopathy and hydranencephaly-hydrocephaly syndrome, MIM# 225790
Intellectual disability syndromic and non-syndromic v0.4387 FLVCR2 Zornitza Stark reviewed gene: FLVCR2: Rating: GREEN; Mode of pathogenicity: None; Publications: 30712878, 20206334, 20518025, 20690116, 25677735; Phenotypes: Proliferative vasculopathy and hydranencephaly-hydrocephaly syndrome, MIM# 225790; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4377 ZBTB18 Zornitza Stark Phenotypes for gene: ZBTB18 were changed from to Mental retardation, autosomal dominant 22, MIM# 612337; Intellectual disability; microcephaly; corpus callosum abnormalities
Intellectual disability syndromic and non-syndromic v0.4374 ZBTB18 Zornitza Stark reviewed gene: ZBTB18: Rating: GREEN; Mode of pathogenicity: None; Publications: 29573576; Phenotypes: Mental retardation, autosomal dominant 22, MIM# 612337, Intellectual disability, microcephaly, corpus callosum abnormalities; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4351 ARFGEF2 Zornitza Stark Phenotypes for gene: ARFGEF2 were changed from to Periventricular heterotopia with microcephaly (MIM#608097)
Intellectual disability syndromic and non-syndromic v0.4348 ARFGEF2 Zornitza Stark reviewed gene: ARFGEF2: Rating: GREEN; Mode of pathogenicity: None; Publications: 25160555, 26126837, 23812912; Phenotypes: Periventricular heterotopia with microcephaly (MIM#608097); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4338 PLK1 Zornitza Stark gene: PLK1 was added
gene: PLK1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PLK1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PLK1 were set to 33875846
Phenotypes for gene: PLK1 were set to Epilepsy; microcephaly; intellectual disability
Review for gene: PLK1 was set to GREEN
Added comment: More than 5 individuals reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4334 TMEM218 Zornitza Stark gene: TMEM218 was added
gene: TMEM218 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: TMEM218 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TMEM218 were set to 33791682; 25161209
Phenotypes for gene: TMEM218 were set to Joubert syndrome 39, MIM#619562
Review for gene: TMEM218 was set to GREEN
Added comment: 11 cases in 6 families with homozygous or compound heterozygous missense and nonsense (1) variants, with a Joubert/Meckel syndrome phenotype. Clinical features included the molar tooth sign (N=2), occipital encephalocele (N=5, all fetuses), retinal dystrophy (N=4, all living individuals), polycystic kidneys (N=2), and polydactyly (N=2), without liver involvement. A null mouse model had nephronophthisis and retinal degeneration. No OMIM entry.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.4322 OGDHL Melanie Marty edited their review of gene: OGDHL: Added comment: Nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing
loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Homozygous and compound heterozygous variants reported. Variant types reported include missense, PTCs and a synonymous variant that was shown to affect splicing.

Functional studies with a CRISPR-Cas9-mediated tissue knockout with cDNA rescue system showed that the missense variants result in loss-of-function.; Changed rating: GREEN
Intellectual disability syndromic and non-syndromic v0.4322 OGDHL Melanie Marty commented on gene: OGDHL: Nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing
loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Homozygous and compound heterozygous variants reported. Variant types reported include missense, PTCs and a synonymous variant that was shown to affect splicing.

Functional studies with a CRISPR-Cas9-mediated tissue knockout with cDNA rescue system showed that the missense variants result in loss-of-function.
Intellectual disability syndromic and non-syndromic v0.4322 OGDHL Melanie Marty changed review comment from: Nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing
loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Homozygous and compound heterozygous variants reported. Variant types reported include missense, PTCs and a synonymous variant that was shown to affect splicing.

Functional studies with a CRISPR-Cas9-mediated tissue knockout with cDNA rescue system showed that the missense variants result in loss-of-function.
Sources: Literature; to: Nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing
loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Homozygous and compound heterozygous variants reported. Variant types reported include missense, PTCs and a synonymous variant that was shown to affect splicing.

Functional studies with a CRISPR-Cas9-mediated tissue knockout with cDNA rescue system showed that the missense variants result in loss-of-function.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4322 OGDHL Melanie Marty gene: OGDHL was added
gene: OGDHL was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: OGDHL was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: OGDHL were set to PMID: 34800363
Phenotypes for gene: OGDHL were set to Neurodevelopmental disorder featuring epilepsy, hearing loss and visual impairment
Added comment: Nine individuals from eight unrelated families carrying bi-allelic variants in OGDHL with a range of neurological and neurodevelopmental phenotypes including epilepsy, hearing
loss, visual impairment, gait ataxia, microcephaly, and hypoplastic corpus callosum.

Homozygous and compound heterozygous variants reported. Variant types reported include missense, PTCs and a synonymous variant that was shown to affect splicing.

Functional studies with a CRISPR-Cas9-mediated tissue knockout with cDNA rescue system showed that the missense variants result in loss-of-function.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4322 FOXR2 Paul De Fazio changed review comment from: 1 patient described with a de novo missense variant. Phenotypes include: postnatal microcephaly, progressive brain atrophy, skeletal abnormalities, brain abnormalities, ophthalmic abnormalities, neuromuscular abnormalities, and dysmorphic features. A variant in ATP1A3 was considered to have contributed to the final phenotype.

In vitro functional evidence is supportive of pathogenicity (variant causes protein instability and abnormal nuclear aggregation).

A mouse knockout has comparable phenotypes, and a severe survival deficit.

Rated amber (1 patient, functional evidence, mouse model).
Sources: Literature; to: Geme added incorrectly.
Intellectual disability syndromic and non-syndromic v0.4322 FOXR1 Paul De Fazio gene: FOXR1 was added
gene: FOXR1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FOXR1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: FOXR1 were set to 34723967
Phenotypes for gene: FOXR1 were set to Postnatal microcephaly, progressive brain atrophy and global developmental delay
Mode of pathogenicity for gene: FOXR1 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: FOXR1 was set to AMBER
gene: FOXR1 was marked as current diagnostic
Added comment: 1 patient described with a de novo missense variant. Phenotypes include: postnatal microcephaly, progressive brain atrophy, skeletal abnormalities, brain abnormalities, ophthalmic abnormalities, neuromuscular abnormalities, and dysmorphic features. A variant in ATP1A3 was considered to have contributed to the final phenotype.

In vitro functional evidence is supportive of pathogenicity (variant causes protein instability and abnormal nuclear aggregation).

A mouse knockout has comparable phenotypes, and a severe survival deficit.

Rated amber (1 patient, functional evidence, mouse model).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4322 FOXR2 Paul De Fazio gene: FOXR2 was added
gene: FOXR2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FOXR2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: FOXR2 were set to 34723967
Phenotypes for gene: FOXR2 were set to Postnatal microcephaly, progressive brain atrophy and global developmental delay
Review for gene: FOXR2 was set to AMBER
gene: FOXR2 was marked as current diagnostic
Added comment: 1 patient described with a de novo missense variant. Phenotypes include: postnatal microcephaly, progressive brain atrophy, skeletal abnormalities, brain abnormalities, ophthalmic abnormalities, neuromuscular abnormalities, and dysmorphic features. A variant in ATP1A3 was considered to have contributed to the final phenotype.

In vitro functional evidence is supportive of pathogenicity (variant causes protein instability and abnormal nuclear aggregation).

A mouse knockout has comparable phenotypes, and a severe survival deficit.

Rated amber (1 patient, functional evidence, mouse model).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4288 ATP1A2 Zornitza Stark Phenotypes for gene: ATP1A2 were changed from Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria to Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy 98, MIM# 619605
Intellectual disability syndromic and non-syndromic v0.4287 ATP1A2 Zornitza Stark edited their review of gene: ATP1A2: Changed phenotypes: Alternating hemiplegia of childhood 1, MIM# 104290, Developmental and epileptic encephalopathy 98, MIM# 619605
Intellectual disability syndromic and non-syndromic v0.4269 CENPJ Zornitza Stark Phenotypes for gene: CENPJ were changed from to Microcephaly 6, primary, autosomal recessive, MIM# 608393, MONDO:0012029; Seckel syndrome 4, MIM# 613676, MONDO:0013358
Intellectual disability syndromic and non-syndromic v0.4266 CENPJ Zornitza Stark reviewed gene: CENPJ: Rating: GREEN; Mode of pathogenicity: None; Publications: 20522431, 23166506, 15793586, 20978018, 22775483, 32677750, 32549991; Phenotypes: Microcephaly 6, primary, autosomal recessive, MIM# 608393, MONDO:0012029, Seckel syndrome 4, MIM# 613676, MONDO:0013358; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4266 CDKL5 Zornitza Stark Phenotypes for gene: CDKL5 were changed from to Developmental and epileptic encephalopathy 2, MIM# 300672
Intellectual disability syndromic and non-syndromic v0.4263 CDKL5 Zornitza Stark reviewed gene: CDKL5: Rating: GREEN; Mode of pathogenicity: None; Publications: 19793311; Phenotypes: Developmental and epileptic encephalopathy 2, MIM# 300672; Mode of inheritance: X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Intellectual disability syndromic and non-syndromic v0.4255 MYH10 Krithika Murali gene: MYH10 was added
gene: MYH10 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list,Literature
Mode of inheritance for gene: MYH10 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MYH10 were set to 24825879; 24901346; 25356899; 22495309; 25003005
Phenotypes for gene: MYH10 were set to Microcephaly; Intellectual Disability
Review for gene: MYH10 was set to GREEN
Added comment: De novo variants were identified in 5 unrelated individuals with moderate-severe ID and developmental delay.

Other reported phenotypic features include microcephaly (4/5), IUGR/failure to thrive (4/5), cerebral atrophy (3/5), hydrocephalus (2/5), congenital bilateral hip dysplasia (2/5), cerebellar atrophy (1/5), congenital diaphragmatic hernia (1/5), cranial nerve palsy (1/5), nystagmus (1/5), dysplastic kidney (1/5).

Defects in heart development, body wall closure and other birth defects noted in mouse models.
Sources: Expert list, Literature
Intellectual disability syndromic and non-syndromic v0.4254 CSF1R Zornitza Stark gene: CSF1R was added
gene: CSF1R was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CSF1R was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CSF1R were set to 30982609; 33749994; 34135456
Phenotypes for gene: CSF1R were set to Brain abnormalities, neurodegeneration, and dysosteosclerosis, MIM# 618476; BANDDOS
Review for gene: CSF1R was set to AMBER
Added comment: Brain abnormalities, neurodegeneration, and dysosteosclerosis (BANDDOS) is an autosomal recessive disorder characterized by brain abnormalities, progressive neurologic deterioration, and sclerotic bone dysplasia similar to dysosteosclerosis (DOS). The age at onset is highly variable: some patients may present in infancy with hydrocephalus, global developmental delay, and hypotonia, whereas others may have onset of symptoms in the late teens or early twenties after normal development. Neurologic features include loss of previous motor and language skills, cognitive impairment, spasticity, and focal seizures. Brain imaging shows periventricular white matter abnormalities and calcifications, large cisterna magna or Dandy-Walker malformation, and sometimes agenesis of the corpus callosum.

Four unrelated families reported.

Note mono-allelic variants cause an adult-onset disorder.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4251 KCNQ2 Zornitza Stark Phenotypes for gene: KCNQ2 were changed from to Developmental and epileptic encephalopathy 7, MIM# 613720; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.4248 KCNQ2 Zornitza Stark reviewed gene: KCNQ2: Rating: GREEN; Mode of pathogenicity: None; Publications: 33659638, 33754465; Phenotypes: Developmental and epileptic encephalopathy 7, MIM# 613720, Intellectual disability; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4248 OTUD7A Zornitza Stark Phenotypes for gene: OTUD7A were changed from Epileptic encephalopathy, intellectual disability, no OMIM# yet to Intellectual disability; Epilepsy
Intellectual disability syndromic and non-syndromic v0.4244 NUP85 Zornitza Stark gene: NUP85 was added
gene: NUP85 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NUP85 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NUP85 were set to 34170319; 30179222
Phenotypes for gene: NUP85 were set to Intellectual disability
Review for gene: NUP85 was set to AMBER
Added comment: Bi-allelic variants in this gene are associated with nephrotic syndrome in 3 families.

Phenotype expansion:

PMID: 34170319 - Ravindran et al 2021 report two pedigrees with an MCPH-SCKS phenotype spectrum without SRNS. In the first family, a 9 yo female, with consanguineous parents, is reported to have a missense variant in NUP85 (c.932G > A; p.R311Q). Intrauterine growth restriction was noticed. At birth microcephaly was observed (OFC < 3rd centile, < −3.6 SD) as well as hypotrophy [weight −2.8 SD), length 45 cm (−2.7 SD), both <3rd centile], facial dysmorphism, syndactyly, long and thin fingers, and bilateral pes adductus. She has severe developmental delay with strongly delayed motor milestones and absent speech. Drug-resistant, genetic epilepsy with focal-onset seizures started in the first year of life. She had no clinical, laboratory or radiological findings indicative of kidney dysfunction. In the second family, compound heterozygous missense variants in NUP85 were detected (c.1109A > G, c.1589 T > C;p.N370S, p.M530T ) in a fetus. MRI of the fetal brain at 24 + 2 GW indicated complete agenesis of the corpus callosum, abnormal sulcation in the left frontal lobe, nodularity of the frontal horn and trigone with focal puckering of the left lateral ventricle.

PMID: 30179222 - Braun et al 2018 - 2 individuals from 1 of the families reported with steroid-resistant nephrotic syndrome were also reported to have intellectual disability but showed no structural brain defects. The degree of intellectual disability is not stated. They were found to have 2 compound heterozygous alleles (c.405+1G>A and c.1741G>C, p.Ala581Pro) in NUP85.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4233 SPATA5L1 Paul De Fazio changed review comment from: 47 individuals from 26 unrelated families from various ethnicities with biallelic variants reported. Phenotypes include ID, hearing impairment, movement disorder, abnormal MRI, hypotonia, visual impairment, epilepsy, and microcephaly.

In 25 patients for whom full phenotype datasets were available, all 25 had ID.
Sources: Literature; to: 47 individuals from 26 unrelated families from various ethnicities with biallelic variants reported. Phenotypes include ID, hearing impairment, movement disorder, abnormal MRI, hypotonia, visual impairment, epilepsy, and microcephaly.

~53% of patients had ID.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4233 SPATA5L1 Paul De Fazio gene: SPATA5L1 was added
gene: SPATA5L1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SPATA5L1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SPATA5L1 were set to 34626583
Phenotypes for gene: SPATA5L1 were set to Intellectual disability; spastic-dystonic cerebral palsy; epilepsy; hearing loss
Review for gene: SPATA5L1 was set to GREEN
gene: SPATA5L1 was marked as current diagnostic
Added comment: 47 individuals from 26 unrelated families from various ethnicities with biallelic variants reported. Phenotypes include ID, hearing impairment, movement disorder, abnormal MRI, hypotonia, visual impairment, epilepsy, and microcephaly.

In 25 patients for whom full phenotype datasets were available, all 25 had ID.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4222 ETHE1 Zornitza Stark Phenotypes for gene: ETHE1 were changed from to Ethylmalonic encephalopathy , MIM#602473
Intellectual disability syndromic and non-syndromic v0.4219 ETHE1 Zornitza Stark reviewed gene: ETHE1: Rating: GREEN; Mode of pathogenicity: None; Publications: 14732903, 28933811; Phenotypes: Ethylmalonic encephalopathy , MIM#602473; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4218 TAOK1 Zornitza Stark Phenotypes for gene: TAOK1 were changed from Intellectual disability; hypotonia; macrocephaly to Developmental delay with or without intellectual impairment or behavioural abnormalities, MIM#619575; Intellectual disability; hypotonia; macrocephaly
Intellectual disability syndromic and non-syndromic v0.4213 FGF12 Zornitza Stark Phenotypes for gene: FGF12 were changed from to Developmental and epileptic encephalopathy 47, MIM# 617166
Intellectual disability syndromic and non-syndromic v0.4210 FGF12 Zornitza Stark reviewed gene: FGF12: Rating: GREEN; Mode of pathogenicity: None; Publications: 32645220, 27164707, 27830185, 27872899; Phenotypes: Developmental and epileptic encephalopathy 47, MIM# 617166; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.4207 NDUFA8 Krithika Murali gene: NDUFA8 was added
gene: NDUFA8 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NDUFA8 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NDUFA8 were set to 32385911; 33153867
Phenotypes for gene: NDUFA8 were set to Mitochondrial complex I deficiency, nuclear type 37- 619272; Epilepsy; Microcephaly; Developmental Delay
Review for gene: NDUFA8 was set to AMBER
Added comment: 3 individuals from 2 unrelated families reported with phenotypic features including microcephaly (1/3), seizures (2/3), developmental delay (3/3) and MRI-B changes (3/3).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4203 NSRP1 Krithika Murali gene: NSRP1 was added
gene: NSRP1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NSRP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NSRP1 were set to 34385670
Phenotypes for gene: NSRP1 were set to Epilepsy; Cerebral palsy; microcephaly; Intellectual disability
Review for gene: NSRP1 was set to AMBER
Added comment: Novel gene regulating splicing. Biallelic LoF pathogenic variants reported in 6 individuals from 3 unrelated families associated with a phenotype characterized by developmental delay, epilepsy, microcephaly, and spastic cerebral palsy.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4194 THG1L Krithika Murali gene: THG1L was added
gene: THG1L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: THG1L was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: THG1L were set to 33682303
Phenotypes for gene: THG1L were set to Spinocerebellar ataxia, autosomal recessive 28 - 618800; Epilepsy; Intellectual Disability
Review for gene: THG1L was set to AMBER
Added comment: 3 individuals from 2 unrelated families of Ashkenazi Jewish descent with compound heterozygous variants ( p.Cys51Trp and p.Val55Ala) presented with profound developmental delays, microcephaly, intractable epilepsy, and cerebellar hypoplasia.

Homozygous variants associated with ataxia phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4194 CELF2 Zornitza Stark Phenotypes for gene: CELF2 were changed from Developmental and epileptic encephalopathy to Developmental and epileptic encephalopathy 97, MIM#619561
Intellectual disability syndromic and non-syndromic v0.4193 CELF2 Zornitza Stark edited their review of gene: CELF2: Changed phenotypes: Developmental and epileptic encephalopathy 97, MIM#619561
Intellectual disability syndromic and non-syndromic v0.4161 SARS Bryony Thompson gene: SARS was added
gene: SARS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SARS were set to 28236339; 34570399
Phenotypes for gene: SARS were set to Intellectual disability
Review for gene: SARS was set to AMBER
Added comment: Summary - 2 unrelated families with overlapping ID phenotype, and supporting in vitro and patient cell assays.
PMID: 28236339 - an Iranian family (distantly related) segregating a homozygous missense (c.514G>A, p.Asp172Asn) with moderate ID, microcephaly, ataxia, speech impairment, and aggressive behaviour. Also, supporting in vitro functional assays demonstrating altered protein function.
PMID: 34570399 - a consanguineous Turkish family segregating a homozygous missense (c.638G>T, p.(Arg213Leu)) with developmental delay, central deafness, cardiomyopathy, and metabolic decompensation during fever leading to death. Also, reduced protein level and enzymatic activity in patient cells.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4140 ATP6V0C Zornitza Stark gene: ATP6V0C was added
gene: ATP6V0C was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
SV/CNV tags were added to gene: ATP6V0C.
Mode of inheritance for gene: ATP6V0C was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ATP6V0C were set to 33190975; 33090716
Phenotypes for gene: ATP6V0C were set to Epilepsy; Intellectual Disability; microcephaly
Review for gene: ATP6V0C was set to AMBER
Added comment: 9 individuals reported with deletions and ID/seizures/microcephaly, minimum overlapping region implicates ATP6V0C as the causative gene. Single case report of de novo SNV and ID/seizures.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4138 ARFGEF1 Zornitza Stark gene: ARFGEF1 was added
gene: ARFGEF1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ARFGEF1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ARFGEF1 were set to 34113008
Phenotypes for gene: ARFGEF1 were set to Intellectual disability; Epilepsy
Review for gene: ARFGEF1 was set to GREEN
Added comment: 13 individuals reported with variants in this gene and a neurodevelopmental disorder characterised by variable ID, seizures present in around half. Variants were inherited from mildly affected parents in 40% of families.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4137 PRR12 Zornitza Stark Phenotypes for gene: PRR12 were changed from intellectual disability; iris abnormalities to Neuroocular syndrome, MIM#619539; Intellectual disability; Iris abnormalities; Complex microphthalmia
Intellectual disability syndromic and non-syndromic v0.4136 PRR12 Zornitza Stark edited their review of gene: PRR12: Changed phenotypes: Neuroocular syndrome, MIM#619539, Intellectual disability, Iris abnormalities, Complex microphthalmia
Intellectual disability syndromic and non-syndromic v0.4131 KIF4A Zornitza Stark edited their review of gene: KIF4A: Added comment: Further 11 families reported. Major structural brain abnormalities present in at least 3 (hydrocephalus), variable ID in several.; Changed rating: GREEN; Changed publications: 24812067, 34346154
Intellectual disability syndromic and non-syndromic v0.4130 ZMYM2 Zornitza Stark Phenotypes for gene: ZMYM2 were changed from Abnormality of the urinary system; Global developmental delay; Intellectual disability; Microcephaly; Abnormality of the cardiovascular system; Autism; Seizures; Abnormality of the head or neck; Abnormality of the nail; Small hand; Short foot; Clinodactyly to Neurodevelopmental-craniofacial syndrome with variable renal and cardiac abnormalities, MIM# 619522
Intellectual disability syndromic and non-syndromic v0.4119 HMGB1 Chirag Patel gene: HMGB1 was added
gene: HMGB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HMGB1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: HMGB1 were set to PMID: 34164801
Phenotypes for gene: HMGB1 were set to Developmental delay and microcephaly, no OMIM #
Review for gene: HMGB1 was set to GREEN
Added comment: 13q12.3 microdeletion syndrome is a rare cause of syndromic ID. Previous studies identified four genes within the ~300 Kb minimal critical region including two candidate protein coding genes: KATNAL1 and HMGB1. Uguen et al. (2021) report 6 patients with LOF variants involving HMGB1 with features similar to 13q12.3 microdeletion syndrome (i.e. developmental delay, language delay, microcephaly, obesity and dysmorphic features). In silico analyses suggest that HMGB1 is likely to be intolerant to LOF, and previous in vitro data are in line with the role of HMGB1 in neurodevelopment. They suggest that haploinsufficiency of the HMGB1 gene may play a critical role in the pathogenesis of the 13q12.3 microdeletion syndrome.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4106 MAGEL2 Anna Le Fevre reviewed gene: MAGEL2: Rating: GREEN; Mode of pathogenicity: None; Publications: 24076603, 31397880, 29599419, 30302899; Phenotypes: Schaaf-Yang syndrome, Chitayat-Hall Syndrome; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, maternally imprinted (paternal allele expressed)
Intellectual disability syndromic and non-syndromic v0.4106 MAGEL2 Anna Le Fevre reviewed gene: MAGEL2: Rating: ; Mode of pathogenicity: None; Publications: 24076603, 30302899, 31397880; Phenotypes: Schaaf-Yang syndrome, Chitayat-Hall Syndrome; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, maternally imprinted (paternal allele expressed)
Intellectual disability syndromic and non-syndromic v0.4102 COPB2 Belinda Chong gene: COPB2 was added
gene: COPB2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: COPB2 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: COPB2 were set to PMID: 34450031
Phenotypes for gene: COPB2 were set to Osteoporosis and developmental delay
Review for gene: COPB2 was set to AMBER
Added comment: Loss-of-function variants in COPB2 (MIM: 606990), a component of the COPI coatomer complex, in six individuals from five unrelated families presenting with a clinical spectrum of osteoporosis or os- teopenia, with or without fractures, and developmental delay of variable severity. A hypomorphic, homozygous missense variant in COPB2 was previously reported in two siblings with microcephaly, spasticity, and develop- mental delay (MIM: 617800) in whom we also here identified low bone mass. Data demonstrate that pathogenic variants in COPB2 lead to early onset osteoporosis and variable developmental delay and that COPB2 and the COPI complex are essential regulators of skeletal homeostasis

3 frameshift (2 de novo, 1 not maternal), 1 x splice (de novo), 2 missense (homozygous).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4098 ZNF668 Paul De Fazio changed review comment from: 5 individuals from 3 consanguineous families reported with different biallelic truncating (not NMD) variants in ZNF668. Phenotypes included microcephaly, growth deficiency, severe global developmental delay, brain malformation, and distinct facial dysmorphism.

Immunofluorescence indicated ZNF668 deficiency. An increased DNA damage phenotype was demonstrated in patient fibroblasts.
Sources: Literature; to: 2 consanguineous families reported with different biallelic truncating (not NMD) variants in ZNF668. Phenotypes included microcephaly, growth deficiency, severe global developmental delay, brain malformation, and distinct facial dysmorphism.

Immunofluorescence indicated ZNF668 deficiency. An increased DNA damage phenotype was demonstrated in patient fibroblasts.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4098 ZNF668 Paul De Fazio gene: ZNF668 was added
gene: ZNF668 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZNF668 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ZNF668 were set to 34313816; 26633546
Phenotypes for gene: ZNF668 were set to DNA damage repair defect; microcephaly; growth deficiency; severe global developmental delay; brain malformation; facial dysmorphism
Review for gene: ZNF668 was set to GREEN
gene: ZNF668 was marked as current diagnostic
Added comment: 5 individuals from 3 consanguineous families reported with different biallelic truncating (not NMD) variants in ZNF668. Phenotypes included microcephaly, growth deficiency, severe global developmental delay, brain malformation, and distinct facial dysmorphism.

Immunofluorescence indicated ZNF668 deficiency. An increased DNA damage phenotype was demonstrated in patient fibroblasts.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4085 WDR11 Zornitza Stark Phenotypes for gene: WDR11 were changed from to Intellectual disability; Microcephaly; Short stature
Intellectual disability syndromic and non-syndromic v0.4081 WDR11 Konstantinos Varvagiannis reviewed gene: WDR11: Rating: AMBER; Mode of pathogenicity: None; Publications: 34413497; Phenotypes: Intellectual disability, Microcephaly, Short stature; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.4058 ARF3 Konstantinos Varvagiannis gene: ARF3 was added
gene: ARF3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ARF3 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: ARF3 were set to 34346499
Phenotypes for gene: ARF3 were set to Global developmental delay; Intellectual disability; Seizures; Morphological abnormality of the central nervous system
Penetrance for gene: ARF3 were set to unknown
Added comment: Sakamoto et al (2021 - PMID: 34346499) provide some evidence that monoallelic ARF3 pathogenic variants may be associated with a NDD with brain abnormality.

Using trio exome sequencing, the authors identified 2 individuals with NDD harboring de novo ARF3 variants, namely: NM_001659.2:c.200A>T / p.Asp67Val and c.296G>T / p.Arg99Leu.

Individual 1 (with Asp67Val / age : 4y10m), appeared to be more severelely affected with prenatal onset progressive microcephaly, severe global DD, epilepsy. Upon MRI there was cerebellar and brainstem atrophy. Individual 2 (Arg99Leu / 14y) had severe DD and ID (IQ of 23), epilepsy and upon MRI cerebellar hypoplasia. This subject did not exhibit microcephaly. Common facial features incl. broad nose, full cheeks, small philtrum, strabismus, thin upper lips and abnormal jaw. There was no evidence of systemic involvement in both.

ARF3 encodes ADP-ribosylation factor 3. Adenosine diphosphate ribosylation factors (ARFs) are key proteins for regulation of cargo sorting at the Golgi network, with ARF3 mainly working at the trans-Golgi network. ARFs belong to the small GTP-binding protein (G protein) superfamily. ARF3 switches between an active GTP-bound form and an inactive GDP-bound form, regulated by guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) respectively.

Members of the ARF superfamily regulate various aspects of membrane traffic, among others in neurons.

There are 5 homologs of ARF families, divided in 3 classes. ARF3 and ARF1 belong to class I. Monoallelic ARF1 mutations are associated with Periventricular nodular heterotopia 8 (MIM 618185).

In vivo, in vitro and in silico studies for the 2 variants suggest that both impair the Golgi transport system although each variant most likely exerts a different effect (gain-of-function for Arg99Leu vs loss-of-function/dominant-negative for Asp67Val).

This was also reflected in somewhat different phenotype of the subjects with the respective variants. Common features included severe DD, epilepsy and brain abnormalities although Asp67Val was associated with diffuse brain atrophy as well as congenital microcephaly and Arg99Leu with cerebellar hypoplasia.

Evidence to support the effect of each variant include:

Arg99Leu:
Had identical Golgi localization to that of wt
Had increased binding activity with GGA1, a protein recruited by the GTP-bound active form of ARF3 to the TGN membrane (supporting GoF)
In silico structural analysis suggested it may fail to stabilize the conformation of Asp26, resulting in impaired GTP hydrolysis (GoF).
In transgenic fruit flies, evaluation of the ARF3 variant toxicity using the rough eye phenotype this variant was associated with increased severity of the r-e phenotype similar to a previously studied GoF variant (Gln71Leu)

Asp67Val:
Did not show a Golgi-like pattern of localization (similar to Thr31Asn a previously studied dominant-negative variant)
Displayed decreased protein stability
In silico structural analysis suggested that Asp67Val may lead to compromised binding of GTP or GDP (suggestive of LoF)
In transgenic Drosophila eye-specific expression of Asp67Val (similar to Thr31Asn, a known dominant-negative variant) was lethal possibly due to high toxicity in very small amounts in tissues outside the eye.

There is no associated phenotype in OMIM, G2P or SysID.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4051 VPS50 Konstantinos Varvagiannis gene: VPS50 was added
gene: VPS50 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: VPS50 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: VPS50 were set to 34037727
Phenotypes for gene: VPS50 were set to Neonatal cholestatic liver disease; Failure to thrive; Profound global developmental delay; Postnatal microcephaly; Seizures; Abnormality of the corpus callosum
Penetrance for gene: VPS50 were set to Complete
Review for gene: VPS50 was set to AMBER
Added comment: Schneeberger et al (2021 - PMID: 34037727) describe the phenotype of 2 unrelated individuals with biallelic VPS50 variants.

Common features included transient neonatal cholestasis, failure to thrive, severe DD with failure to achieve milestones (last examination at 2y and 2y2m respectively), postnatal microcephaly, seizures (onset at 6m and 25m) and irritability. There was corpus callosum hypoplasia on brain imaging.

Both individuals were homozygous for variants private to each family (no/not known consanguinity applying to each case). The first individual was homozygous for a splicing variant (NM_017667.4:c.1978-1G>T) and had a similarly unaffected sister deceased with no available DNA for testing. The other individual was homozygous for an in-frame deletion (c.1823_1825delCAA / p.(Thr608del)).

VPS50 encodes a critical component of the endosome-associated recycling protein (EARP) complex, which functions in recycling endocytic vesicles back to the plasma membrane [OMIM based on Schindler et al]. The complex contains VPS50, VPS51, VPS52, VPS53, the three latter also being components of GARP (Golgi-associated-retrograde protein) complex. GARP contains VPS54 instead of VPS50 and is required for trafficking of proteins to the trans-golgi network. Thus VPS50 (also named syndetin) and VPS54 function in the EARP and GARP complexes, to define directional movement of their endocytic vesicles [OMIM based on Schindler et al]. The VPS50 subunit is required for recycling of the transferrin receptor.

As discussed by Schneeberger et al (refs provided in text):
- VPS50 has a high expression in mouse and human brain as well as throughout mouse brain development.
- Mice deficient for Vps50 have not been reported. vps50 knockdown in zebrafish results in severe developmental defects of the body axis. Knockout mice for other proteins of the EARP/GARP complex (e.g. Vps52, 53 and 54) display embryonic lethality.

Studies performed by Schneeberger et al included:
- Transcript analysis for the 1st variant demonstrated skipping of ex21 (in patient derived fabriblasts) leading to an in frame deletion of 81 bp (r.1978_2058del) with predicted loss of 27 residues (p.Leu660_Leu686del).
- Similar VPS50 mRNA levels but significant reduction of protein levels (~5% and ~8% of controls) were observed in fibroblasts from patients 1 and 2. Additionally, significant reductions in the amounts of VPS52 and VPS53 protein levels were observed despite mRNA levels similar to controls. Overall, this suggested drastic reduction of functional EARP complex levels.
- Lysosomes appeared to have similar morphology, cellular distribution and likely unaffected function in patient fibroblasts.
- Transferrin receptor recycling was shown to be delayed in patient fibroblasts suggestive of compromise of endocytic-recycling function.

As the authors comment, the phenotype of both individuals with biallelic VPS50 variants overlaps with the corresponding phenotype reported in 15 subjects with biallelic VPS53 or VPS51 mutations notably, severe DD/ID, microcephaly and early onset epilepsy, CC anomalies. Overall, for this group, they propose the term "GARP and/or EARP deficiency disorders".

There is no VPS50-associated phenotype in OMIM or G2P. SysID includes VPS50 among the ID candidate genes.

Consider inclusion in other relevant gene panels (e.g. for neonatal cholestasis, epilepsy, microcephaly, growth failure in early infancy, corpus callosum anomalies, etc) with amber rating pending further reports.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4047 TMEM222 Zornitza Stark Phenotypes for gene: TMEM222 were changed from Motor delay; Delayed speech and language development; Intellectual disability; Generalized hypotonia; Broad-based gait; Abnormality of nervous system morphology; Seizures; Microcephaly; Behavioral abnormality to Neurodevelopmental disorder with motor and speech delay and behavioural abnormalities, MIM# 619470; Motor delay; Delayed speech and language development; Intellectual disability; Generalized hypotonia; Broad-based gait; Abnormality of nervous system morphology; Seizures; Microcephaly; Behavioral abnormality
Intellectual disability syndromic and non-syndromic v0.4040 PIDD1 Konstantinos Varvagiannis gene: PIDD1 was added
gene: PIDD1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PIDD1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PIDD1 were set to 28397838; 29302074; 33414379; 34163010
Phenotypes for gene: PIDD1 were set to Global developmental delay; Intellectual disability; Seizures; Autism; Behavioral abnormality; Psychosis; Pachygyria; Lissencephaly; Abnormality of the corpus callosum
Penetrance for gene: PIDD1 were set to Complete
Review for gene: PIDD1 was set to GREEN
Added comment: There is enough evidence to include this gene in the current panel with green rating.

Biallelic PIDD1 pathogenic variants have been reported in 26 individuals (11 families) with DD (all), variable degrees of ID (mild to severe), behavioral (eg. aggression/self-mutilation in several, ADHD) and/or psychiatric abnormalities (ASD, psychosis in 5 belonging to 3 families), well-controlled epilepsy is some (9 subjects from 6 families) and MRI abnormalities notably abnormal gyration pattern (pachygyria with predominant anterior gradient) as well as corpus callosum anomalies (commonly thinning) in several. Dysmorphic features have been reported in almost all, although there has been no specific feature suggested.

The first reports on the phenotype associated with biallelic PIDD1 mutations were made by Harripaul et al (2018 - PMID: 28397838) and Hu et al (2019 - PMID: 29302074) [both studies investigating large cohorts of individuals with ID from consanguineous families].

Sheikh et al (2021 - PMID: 33414379) provided details on the phenotype of 15 individuals from 5 families including those from the previous 2 reports and studied provided evidence on the role of PIDD1 and the effect of variants.

Zaki et al (2021 - PMID: 34163010) reported 11 additional individuals from 6 consanguineous families, summarize the features of all subjects published in the literature and review the neuroradiological features of the disorder.

PIDD1 encodes p53-induced death domain protein 1. The protein is part of the PIDDosome, a multiprotein complex also composed of the bipartite linker protein CRADD (also known as RAIDD) and the proform of caspase-2 and induces apoptosis in response to DNA damage.

There are 5 potential PIDD1 mRNA transcript variants with NM_145886.4 corresponding to the longest. Similar to the protein encoded by CRADD, PIDD1 contains a death domain (DD - aa 774-893). Constitutive post-translational processing gives PIDD1-N, PIDD1-C the latter further processed into PIDD1-CC (by auto-cleavage). Serine residues at pos. 446 and 588 are involved in this autoprocessing generating PIDD1-C (aa 446-910) and PIDD1-CC (aa 774-893). The latter is needed for caspase-2 activation.

Most (if not all) individuals belonged to consanguineous families of different origins and harbored pLoF or missense variants.

Variants reported so far include : c.2587C>T; p.Gln863* / c.1909C>T ; p.Arg637* / c.2443C>T / p.Arg815Trp / c.2275-1G>A which upon trap assay was shown to lead to skipping of ex15 with direct splicing form exon14 to the terminal exon 16 (resulting to p.Arg759Glyfs*1 with exlcusion of the entire DD) / c.2584C>T; p.Arg862Trp / c.1340G>A; p.Trp447* / c.2116_2120del; p.Val706His*, c.1564_1565del; p.Gly602fs*26

Evidence so far provided includes:
- Biallelic CRADD variants cause a NDD disorder and a highly similar gyration pattern.
- Confirmation of splicing effect (eg. for c.2275-1G>A premature stop in position 760) or poor expression (NM_145886.3:c.2587C>T; p.Gln863*). Arg815Trp did not affect autoprocessing or protein stability.
- Abnormal localization pattern, loss of interaction with CRADD and failure to activate caspase-2 (MDM2 cleavage assay) [p.Gln863* and Arg815Trp]
- Available expression data from GTEx (PIDD1 having broad expression in multiple tissues, but higher in brain cerebellum) as well as BrainSpan and PsychEncode studies suggesting high coexpression of PIDD1, CRADD and CASP2 in many regions in the developing human brain.
- Variants in other genes encoding proteins interacting with PIDD1 (MADD, FADD, DNAJ, etc) are associated with NDD.

Pidd-1 ko mice (ex3-15 removal) lack however CNS-related phenotypes. These show decreased anxiety but no motor anomalies. This has also been the case with Cradd-/- mice displaying no significant CNS phenotypes without lamination defects.

There is currently no associated phenotype in OMIM, PanelApp Australia. PIDD1 is listed in the DD panel of G2P (PIDD1-related NDD / biallelic / loss of function / probable) . SysID includes PIDD1 among the current primary ID genes.

Overall the gene appears to be relevant for the epilepsy panel, panels for gyration and/or corpus callosum anomalies etc.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4030 TP73 Zornitza Stark Phenotypes for gene: TP73 were changed from Intellectual disability; lissencephaly to Ciliary dyskinesia, primary, 47, and lissencephaly, MIM#619466; Intellectual disability; lissencephaly
Intellectual disability syndromic and non-syndromic v0.4029 TP73 Zornitza Stark edited their review of gene: TP73: Added comment: Additional 5 families reported in PMID 34077761; Changed rating: GREEN; Changed publications: 31130284, 34077761; Changed phenotypes: Ciliary dyskinesia, primary, 47, and lissencephaly, MIM#619466, Intellectual disability, lissencephaly
Intellectual disability syndromic and non-syndromic v0.4028 MAST3 Zornitza Stark gene: MAST3 was added
gene: MAST3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MAST3 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MAST3 were set to 34185323
Phenotypes for gene: MAST3 were set to Developmental and epileptic encephalopathy
Review for gene: MAST3 was set to GREEN
Added comment: Eleven individuals reported with de novo missense variants in the STK domain, including two recurrent variants p.G510S (n = 5) and p.G515S (n = 3). All 11 individuals had developmental and epileptic encephalopathy, with 8 having normal development prior to seizure onset at <2 years of age. All patients developed multiple seizure types, 9 of 11 patients had seizures triggered by fever and 9 of 11 patients had drug-resistant seizures. Limited functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4023 AP1G1 Zornitza Stark changed review comment from: Two bi-allelic homozygous missense variants were found in two distinct families with Italian and Pakistani origins; homozygous missense variants.

Eight de novo heterozygous variants were identified in nine isolated affected individuals from nine families; including five missense, two frameshift, and one intronic variant that disrupts the canonical splice acceptor site.

Knocking out AP1G1 Zebrafish model resulted in severe developmental abnormalities and increased lethality.

All individuals had neurodevelopmental disorder (NDD) including global developmental delay and ID, which varied in severity from mild to severe.
Sources: Literature; to: Two bi-allelic homozygous missense variants were found in two distinct families with Italian and Pakistani origins; homozygous missense variants.

Eight de novo heterozygous variants were identified in nine isolated affected individuals from nine families; including five missense, two frameshift, and one intronic variant that disrupts the canonical splice acceptor site.

Knocking out AP1G1 Zebrafish model resulted in severe developmental abnormalities and increased lethality.

All individuals had neurodevelopmental disorder (NDD) including global developmental delay and ID, which varied in severity from mild to severe.

GREEN for mono-allelic, AMBER for bi-allelic.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4023 AP1G1 Zornitza Stark gene: AP1G1 was added
gene: AP1G1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: AP1G1 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: AP1G1 were set to 34102099
Phenotypes for gene: AP1G1 were set to Neurodevelopmental disorder (NDD); Intellectual Disability; Epilepsy
Review for gene: AP1G1 was set to GREEN
Added comment: Two bi-allelic homozygous missense variants were found in two distinct families with Italian and Pakistani origins; homozygous missense variants.

Eight de novo heterozygous variants were identified in nine isolated affected individuals from nine families; including five missense, two frameshift, and one intronic variant that disrupts the canonical splice acceptor site.

Knocking out AP1G1 Zebrafish model resulted in severe developmental abnormalities and increased lethality.

All individuals had neurodevelopmental disorder (NDD) including global developmental delay and ID, which varied in severity from mild to severe.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4020 CLCN3 Zornitza Stark gene: CLCN3 was added
gene: CLCN3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CLCN3 was set to BOTH monoallelic and biallelic (but BIALLELIC mutations cause a more SEVERE disease form), autosomal or pseudoautosomal
Publications for gene: CLCN3 were set to 34186028
Phenotypes for gene: CLCN3 were set to Neurodevelopmental disorder
Mode of pathogenicity for gene: CLCN3 was set to Other
Review for gene: CLCN3 was set to GREEN
Added comment: 11 individuals reported, 9 that carried 8 different rare heterozygous missense variants in CLCN3, and 2 siblings that were homozygous for an NMD-predicted frameshift variant likely abolishing ClC-3 function. All missense variants were confirmed to be de novo in eight individuals for whom parental data was available.

The 11 individuals in the cohort share clinical features of variable severity. All 11 have GDD or ID and dysmorphic features, and a majority has mood or behavioural disorders and structural brain abnormalities:
- Structural brain abnormalities on MRI (9/11) included partial or full agenesis of the corpus callosum (6/9), disorganized cerebellar folia (4/9), delayed myelination (3/9), decreased white matter volume (3/9), pons hypoplasia (3/9), and dysmorphic dentate nuclei (3/9). Six of those with brain abnormalities also presented with seizures.
- Nine have abnormal vision, including strabismus in four and inability to fix or follow in the two with homozygous loss-of-function variants.
- Hypotonia ranging from mild to severe was reported in 7 of the 11 individuals.
- Six have mood or behavioural disorders, particularly anxiety (3/6).
- Consistent dysmorphic facial features included microcephaly, prominent forehead, hypertelorism, down-slanting palpebral fissures, full cheeks, and micrognathia.

The severity of disease in the two siblings with homozygous disruption of ClC-3 is consistent with the drastic phenotype seen in Clcn3 KO mice. The disease was more severe in two siblings carrying homozygous loss-of-function variants with the presence of GDD, absent speech, seizures, and salt and pepper fundal pigmentation in both individuals, with one deceased at 14 months of age. The siblings also had significant neuroanatomical findings including diffusely decreased white matter volume, thin corpora callosa, small hippocampi, and disorganized cerebellar folia. Supporting biallelic inheritance for LoF variants, disruption of mouse Clcn3 results in drastic neurodegeneration with loss of the hippocampus a few months after birth and early retinal degeneration. Clcn3−/− mice display severe neurodegeneration, whereas heterozygous Clcn3+/− mice appear normal.

Patch-clamp studies were used to investigate four of the missense variants. These suggested a gain of function in two variants with increased current in HEK cells, however they also showed reduced rectification of voltage and a loss of transient current, plus decreased current amplitude, glycosylation and surface expression when expressed in oocytes, and were suspected to interfere with channel gating and a negative feedback mechanism. These effects were also shown to vary depending on pH levels. The current of the remaining two variants did not differ from WT. For heterozygous missense variants, the disruption induced may be at least partially conferred to mutant/WT homodimers and mutant/ClC-4 heterodimers.

Both loss and gain of function in this gene resulted in the same phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4017 TNPO2 Elena Savva gene: TNPO2 was added
gene: TNPO2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TNPO2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: TNPO2 were set to PMID: 34314705
Phenotypes for gene: TNPO2 were set to Developmental delays, neurologic deficits and dysmorphic features
Mode of pathogenicity for gene: TNPO2 was set to Other
Review for gene: TNPO2 was set to GREEN
Added comment: PMID: 34314705 - all de novo missense variants with intellectual disability (9/9), speech impairment (15/15), motor impairment (15/15), ophthalmologic abnormalities (10/15), muscle tone abnormalities (11/15, primarily hypotonia), seizures (6/15, febrile to non-febrile), microcephaly (5/15) and MRI anomalies (7/13, 3/13 had cerebellar hypoplasia/dysplasia).

Null fly model was homozygous lethal, no obvious phenotypes in heterozygotes. Upregulated gene expression also resulted in lethality. Overexpression of some human variants in fly models resulted in "toxicity" and phenotypic defects, authors speculate two variants are GOF, 1 variant is LOF.

gnomAD: minimal PTCs present
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4016 SPTBN1 Belinda Chong changed review comment from: PMID: 34211179
- Heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures; behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features.
- Show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics.

PMID: 33847457
- Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset.
- identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities).
- Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis.
Sources: Literature
Sources: Literature; to: PMID: 34211179
- Heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures (9/29); behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features.
- Show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics.

PMID: 33847457
- Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset.
- identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities).
- Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis.
Sources: Literature
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4015 SPTBN1 Belinda Chong gene: SPTBN1 was added
gene: SPTBN1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SPTBN1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SPTBN1 were set to PMID: 34211179 PMID: 33847457
Phenotypes for gene: SPTBN1 were set to Neurodevelopmental Syndrome
Review for gene: SPTBN1 was set to GREEN
Added comment: PMID: 34211179
- Heterozygous SPTBN1 variants in 29 individuals with developmental, language and motor delays; mild to severe intellectual disability; autistic features; seizures; behavioral and movement abnormalities; hypotonia; and variable dysmorphic facial features.
- Show that these SPTBN1 variants lead to effects that affect βII-spectrin stability, disrupt binding to key molecular partners, and disturb cytoskeleton organization and dynamics.

PMID: 33847457
- Common features include global developmental delays, intellectual disability, and behavioral disturbances. Autistic features (4/6) and epilepsy (2/7) or abnormal electroencephalogram without overt seizures (1/7) were present in a subset.
- identified seven unrelated individuals with heterozygous SPTBN1 variants: two with de novo missense variants and five with predicted loss-of-function variants (found to be de novo in two, while one was inherited from a mother with a history of learning disabilities).
- Identification of loss-of-function variants suggests a haploinsufficiency mechanism, but additional functional studies are required to fully elucidate disease pathogenesis.
Sources: Literature
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.4009 ANK2 Anna Le Fevre commented on gene: ANK2: Publications largely cover autism risk and discovery in large cohorts. ClinGen review mentions ID, seizures and microcephaly but phenotype and penetrance appear incompletely described.
Intellectual disability syndromic and non-syndromic v0.3982 CEP85L Zornitza Stark gene: CEP85L was added
gene: CEP85L was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: CEP85L was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CEP85L were set to 32097630
Phenotypes for gene: CEP85L were set to Lissencephaly, posterior predominant
Review for gene: CEP85L was set to GREEN
Added comment: Thirteen individuals reported with mono allelic variants in this gene, inherited in two of the families. Mouse model had neuronal migration defects.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.3978 ATG7 Zornitza Stark changed review comment from: 12 individuals from 5 unrelated families reported with a complex neurodevelopmental disorder and bi-allelic variants in this gene. Age range from 21 months to 71 years of age. Main clinical features included axial hypotonia, variably impaired intellectual development with poor or absent speech, and delayed walking (up to 7 years of age) or inability to walk. All had ataxia, often with tremor or dyskinesia, as well as dysarthria associated with cerebellar hypoplasia on brain imaging. Most had optic atrophy, and some had ptosis, chronic progressive external ophthalmoplegia, retinopathy, and strabismus; 1 had early-onset cataracts. The more severely affected individuals had spastic paraplegia and inability to walk.

Functional data including mouse model.
Sources: Literature; to: 12 individuals from 5 unrelated families reported with a complex neurodevelopmental disorder and bi-allelic variants in this gene. Age range from 21 months to 71 years of age. Main clinical features included axial hypotonia, variably impaired intellectual development with poor or absent speech, and delayed walking (up to 7 years of age) or inability to walk. All had ataxia, often with tremor or dyskinesia, as well as dysarthria associated with cerebellar hypoplasia on brain imaging. Most had optic atrophy, and some had ptosis, chronic progressive external ophthalmoplegia, retinopathy, and strabismus; 1 had early-onset cataracts. The more severely affected individuals had spastic paraplegia and inability to walk.

Functional data including mouse model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3978 ATG7 Zornitza Stark changed review comment from: 12 individuals from 5 unrelated families reported with a complex neurodevelopmental disorder and bi-allelic variants in this gene. Age range from 21 months to 71 years of age. Main clinical features included axial hypotonia, variably impaired intellectual development with poor or absent speech, and delayed walking (up to 7 years of age) or inability to walk. All had ataxia, often with tremor or dyskinesia, as well as dysarthria associated with cerebellar hypoplasia on brain imaging. Most had optic atrophy, and some had ptosis, chronic progressive external ophthalmoplegia, retinopathy, and strabismus; 1 had early-onset cataracts. The ore severely affected individuals had spastic paraplegia and inability to walk.

Functional data including mouse model.
Sources: Literature; to: 12 individuals from 5 unrelated families reported with a complex neurodevelopmental disorder and bi-allelic variants in this gene. Age range from 21 months to 71 years of age. Main clinical features included axial hypotonia, variably impaired intellectual development with poor or absent speech, and delayed walking (up to 7 years of age) or inability to walk. All had ataxia, often with tremor or dyskinesia, as well as dysarthria associated with cerebellar hypoplasia on brain imaging. Most had optic atrophy, and some had ptosis, chronic progressive external ophthalmoplegia, retinopathy, and strabismus; 1 had early-onset cataracts. The more severely affected individuals had spastic paraplegia and inability to walk.

Functional data including mouse model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3977 ATG7 Zornitza Stark gene: ATG7 was added
gene: ATG7 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ATG7 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ATG7 were set to 34161705
Phenotypes for gene: ATG7 were set to Spinocerebellar ataxia, SCAR31, MIM#619422
Review for gene: ATG7 was set to GREEN
Added comment: 12 individuals from 5 unrelated families reported with a complex neurodevelopmental disorder and bi-allelic variants in this gene. Age range from 21 months to 71 years of age. Main clinical features included axial hypotonia, variably impaired intellectual development with poor or absent speech, and delayed walking (up to 7 years of age) or inability to walk. All had ataxia, often with tremor or dyskinesia, as well as dysarthria associated with cerebellar hypoplasia on brain imaging. Most had optic atrophy, and some had ptosis, chronic progressive external ophthalmoplegia, retinopathy, and strabismus; 1 had early-onset cataracts. The ore severely affected individuals had spastic paraplegia and inability to walk.

Functional data including mouse model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3975 C2orf69 Zornitza Stark gene: C2orf69 was added
gene: C2orf69 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: C2orf69 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: C2orf69 were set to 34038740; 33945503
Phenotypes for gene: C2orf69 were set to Combined oxidative phosphorylation deficiency-53 (COXPD53), MIM#619423
Review for gene: C2orf69 was set to GREEN
Added comment: PMID 34038740: 20 affected children from 8 unrelated families reported, presenting with fatal syndrome consisting of severe autoinflammation and progredient leukoencephalopathy with recurrent seizures; 12 of these subjects, whose DNA was available, segregated homozygous loss-of-function C2orf69 variants. Endogenous C2ORF69 was found to be (1) loosely bound to mitochondria, (2) affects mitochondrial membrane potential and oxidative respiration in cultured neurons, and (3) controls the levels of the glycogen branching enzyme 1 (GBE1) consistent with a glycogen-storage-associated mitochondriopathy. Zebrafish model.

PMID 33945503: 8 individuals from 5 families reported with muscle hypotonia, developmental delay, progressive microcephaly, and brain MRI abnormalities. Age at onset ranged from birth to 6 months of age. Six patients had vision impairment, liver abnormalities, inflammation/inflammatory arthritis, and 5 patients had seizures.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3967 RING1 Zornitza Stark gene: RING1 was added
gene: RING1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RING1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RING1 were set to 29386386
Phenotypes for gene: RING1 were set to microcephaly; intellectual disability
Review for gene: RING1 was set to RED
Added comment: Not associated with any phenotype in OMIM. PMID: 29386386 - Pierce et al 2018 - report a 13 yo female with a de novo RING1 p.R95Q variant and syndromic neurodevelopmental disabilities. Early motor and language development were normal but were delayed after the first year of life. Cognitive testing showed a verbal IQ of 55 and a visual performance IQ of 63. Head circumference at birth was -4.9 SD, and -4.2 SD at age 13 which falls into the severe microcephaly category. C. elegans with either the missense mutation or complete knockout of spat-3 (the suggested RING1 ortholog) were defective in monoubiquitylation of histone H2A and had defects in neuronal migration and axon guidance.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3955 HID1 Zornitza Stark gene: HID1 was added
gene: HID1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HID1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: HID1 were set to 33999436
Phenotypes for gene: HID1 were set to Syndromic infantile encephalopathy; Hypopituitarism
Review for gene: HID1 was set to GREEN
Added comment: 7 individuals from 6 unrelated families reported. Clinical features included: hypopituitarism in combination with brain atrophy, thin corpus callosum, severe developmental delay, visual impairment, and epilepsy
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3952 ERGIC3 Seb Lunke gene: ERGIC3 was added
gene: ERGIC3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ERGIC3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ERGIC3 were set to ERGIC3
Phenotypes for gene: ERGIC3 were set to 33710394; 31585110
Review for gene: ERGIC3 was set to AMBER
Added comment: PMID: 33710394 - two homozygous sibs with mild ID, a novel canonical splice (c.717+1G>A). Absent in gnomAD, no splice studies. Classed as a VUS.

PMID: 31585110 - 1 hom (p.Gln233Argfs*10) in a male 8yo with Growth retardation, Microcephaly, Learning disability, Facial dysmorphism, Abnormal pigmentation.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3948 ATP1A2 Zornitza Stark Phenotypes for gene: ATP1A2 were changed from Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria to Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3947 ATP1A2 Zornitza Stark Phenotypes for gene: ATP1A2 were changed from Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria to Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3947 ATP1A2 Zornitza Stark Phenotypes for gene: ATP1A2 were changed from Alternating hemiplegia of childhood 1, MIM# 104290 to Alternating hemiplegia of childhood 1, MIM# 104290; Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3945 ATP1A2 Zornitza Stark edited their review of gene: ATP1A2: Added comment: PMID 33880529: six individuals with de novo missense variants reported and DD/EE/PMG.; Changed publications: 33880529; Changed phenotypes: Alternating hemiplegia of childhood 1, MIM# 104290, Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3945 ATP1A3 Zornitza Stark Phenotypes for gene: ATP1A3 were changed from Alternating hemiplegia of childhood 2, MIM#614820 to Alternating hemiplegia of childhood 2, MIM#614820; Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3943 ATP1A3 Zornitza Stark edited their review of gene: ATP1A3: Added comment: PMID 33880529: 16 individuals reported with DD/EE and PMG.; Changed rating: GREEN; Changed publications: 33880529; Changed phenotypes: Alternating hemiplegia of childhood 2, MIM#614820, Developmental and epileptic encephalopathy, polymicrogyria
Intellectual disability syndromic and non-syndromic v0.3936 DNM1 Zornitza Stark Phenotypes for gene: DNM1 were changed from to Developmental and epileptic encephalopathy 31, OMIM:616346
Intellectual disability syndromic and non-syndromic v0.3933 DNM1 Zornitza Stark reviewed gene: DNM1: Rating: GREEN; Mode of pathogenicity: None; Publications: 25262651, 27066543, 33372033, 34172529; Phenotypes: Developmental and epileptic encephalopathy 31, OMIM:616346; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3929 ATP9A Zornitza Stark gene: ATP9A was added
gene: ATP9A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ATP9A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ATP9A were set to http://dx.doi.org/10.1136/jmedgenet-2021-107843
Phenotypes for gene: ATP9A were set to Neurodevelopmental delay; Postnatal microcephaly; Failure to thrive; Gastrointestinal symptoms
Review for gene: ATP9A was set to AMBER
Added comment: Vogt et al. 2021 report on 3 individuals from 2 unrelated consanguineous families with different homozygous truncating variants in ATP9A, presenting with DD/ID of variable degree (2 mild, 1 severe), postnatal microcephaly (OFC range: −2.33 SD to −3.58 SD), failure to thrive, and gastrointestinal symptoms. Patient-derived fibroblasts showed reduced expression of ATP9A, and consistent with previous findings also overexpression of interacting partners, ARPC3 and SNX3.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3921 ARHGEF9 Zornitza Stark Phenotypes for gene: ARHGEF9 were changed from to Developmental and epileptic encephalopathy 8, MIM# 300607
Intellectual disability syndromic and non-syndromic v0.3918 ARHGEF9 Zornitza Stark reviewed gene: ARHGEF9: Rating: GREEN; Mode of pathogenicity: None; Publications: 31942680, 30048823, 29130122, 28620718, 33600053, 32939676; Phenotypes: Developmental and epileptic encephalopathy 8, MIM# 300607; Mode of inheritance: X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Intellectual disability syndromic and non-syndromic v0.3892 PPP2R1A Zornitza Stark Phenotypes for gene: PPP2R1A were changed from to Mental retardation, autosomal dominant 36, MIM#616362; Microcephaly-corpus callosum hypoplasia-intellectual disability-facial dysmorphism syndrome, MONDO:0014605
Intellectual disability syndromic and non-syndromic v0.3889 PPP2R1A Zornitza Stark reviewed gene: PPP2R1A: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Mental retardation, autosomal dominant 36, MIM#616362, Microcephaly-corpus callosum hypoplasia-intellectual disability-facial dysmorphism syndrome, MONDO:0014605; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3885 ARCN1 Zornitza Stark Phenotypes for gene: ARCN1 were changed from to Short stature, rhizomelic, with microcephaly, micrognathia, and developmental delay (MIM#617164)
Intellectual disability syndromic and non-syndromic v0.3882 ARCN1 Zornitza Stark reviewed gene: ARCN1: Rating: GREEN; Mode of pathogenicity: None; Publications: 27476655, 33154040; Phenotypes: Short stature, rhizomelic, with microcephaly, micrognathia, and developmental delay (MIM#617164); Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3882 SLC13A5 Zornitza Stark Phenotypes for gene: SLC13A5 were changed from to Developmental and epileptic encephalopathy 25, with amelogenesis imperfecta MIM#615905; MONDO:0014392
Intellectual disability syndromic and non-syndromic v0.3879 SLC13A5 Zornitza Stark reviewed gene: SLC13A5: Rating: GREEN; Mode of pathogenicity: None; Publications: 24995870, 26384929; Phenotypes: Developmental and epileptic encephalopathy 25, with amelogenesis imperfecta MIM#615905, MONDO:0014392; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3852 EIF5A Zornitza Stark Phenotypes for gene: EIF5A were changed from Intellectual disability; microcephaly; dysmorphism to Faundes-Banka syndrome, MIM# 619376; Intellectual disability; microcephaly; dysmorphism
Intellectual disability syndromic and non-syndromic v0.3851 EIF5A Zornitza Stark edited their review of gene: EIF5A: Changed phenotypes: Faundes-Banka syndrome, MIM# 619376, Intellectual disability, microcephaly, dysmorphism
Intellectual disability syndromic and non-syndromic v0.3846 ATXN2L Sue White gene: ATXN2L was added
gene: ATXN2L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ATXN2L was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ATXN2L were set to 33283965; 33057194
Phenotypes for gene: ATXN2L were set to macrocephaly; intellectual disability
Penetrance for gene: ATXN2L were set to Complete
Review for gene: ATXN2L was set to AMBER
Added comment: Combined data from three large exome groups identified several de novo variants, including frameshift and missense, in ATXN2L in patients with developmental delay (Kaplanis et al., 2020). pLI=1.0
Single case report of a novel de novo missense variant in a child with macrocephaly and developmental delay. No functional work.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3845 BCAS3 Paul De Fazio gene: BCAS3 was added
gene: BCAS3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: BCAS3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: BCAS3 were set to 34022130
Phenotypes for gene: BCAS3 were set to Syndromic neurodevelopmental disorder
Review for gene: BCAS3 was set to GREEN
gene: BCAS3 was marked as current diagnostic
Added comment: 15 individuals from eight unrelated families with germline bi-allelic loss-of-function variants in BCAS3. All probands share a global developmental delay accompanied by pyramidal tract involvement, microcephaly, short stature, strabismus, dysmorphic facial features, and seizures. Patient fibroblasts confirmed absence of BCAS3 protein.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3825 IQSEC2 Zornitza Stark Phenotypes for gene: IQSEC2 were changed from to Mental retardation, X-linked 1/78, MIM# 309530, MONDO:0010656; Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347
Intellectual disability syndromic and non-syndromic v0.3822 IQSEC2 Zornitza Stark edited their review of gene: IQSEC2: Added comment: More than 20 unrelated families reported.; Changed publications: 31415821, 20473311, 30842726, 33368194, 23674175; Changed phenotypes: Mental retardation, X-linked 1/78, MIM# 309530, MONDO:0010656, Severe intellectual disability-progressive postnatal microcephaly- midline stereotypic hand movements syndrome MONDO:0018347
Intellectual disability syndromic and non-syndromic v0.3820 EHMT1 Zornitza Stark commented on gene: EHMT1: Well established gene-disease association. Deletions are common. Key features includeID/seizures/microcephaly/dysmorphism/congenital anomalies. More than 100 individuals reported.
Intellectual disability syndromic and non-syndromic v0.3820 EEF1A2 Zornitza Stark Phenotypes for gene: EEF1A2 were changed from Epileptic encephalopathy, early infantile, 33, MIM# 616409; Mental retardation, autosomal dominant 38, MIM# 616393 to Mental retardation, autosomal dominant 38, MIM# 616393; MONDO:0014617; Developmental and epileptic encephalopathy 33, MIM# 616409; MONDO:0014625
Intellectual disability syndromic and non-syndromic v0.3818 EEF1A2 Zornitza Stark edited their review of gene: EEF1A2: Changed phenotypes: Mental retardation, autosomal dominant 38, MIM# 616393, MONDO:0014617, Developmental and epileptic encephalopathy 33, MIM# 616409, MONDO:0014625
Intellectual disability syndromic and non-syndromic v0.3799 NSF Zornitza Stark Phenotypes for gene: NSF were changed from Seizures; EEG with burst suppression; Global developmental delay; Intellectual disability to Developmental and epileptic encephalopathy 96, MIM# 619340; Seizures; EEG with burst suppression; Global developmental delay; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.3798 NSF Zornitza Stark edited their review of gene: NSF: Changed phenotypes: Developmental and epileptic encephalopathy 96, MIM# 619340, Seizures, EEG with burst suppression, Global developmental delay, Intellectual disability
Intellectual disability syndromic and non-syndromic v0.3787 PARP6 Zornitza Stark gene: PARP6 was added
gene: PARP6 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PARP6 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PARP6 were set to Cells 2021, 10(6), 1289; https://doi.org/10.3390/cells10061289
Phenotypes for gene: PARP6 were set to Intellectual disability; Epilepsy; Microcephaly
Review for gene: PARP6 was set to GREEN
Added comment: Four unrelated individuals reported with de novo variants in this gene and a neurodevelopmental phenotype. Supportive functional data. One pair of siblings with a homozygous missense: limited evidence for bi-allelic variants causing disease.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3781 SCN1A Zornitza Stark Phenotypes for gene: SCN1A were changed from to Epileptic encephalopathy, early infantile, 6 (Dravet syndrome) 607208 Developmental and epileptic encephalopathy 6B, non-Dravet, MIM# 619317
Intellectual disability syndromic and non-syndromic v0.3780 SCN1A Zornitza Stark reviewed gene: SCN1A: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Epileptic encephalopathy, early infantile, 6 (Dravet syndrome) 607208 Developmental and epileptic encephalopathy 6B, non-Dravet, MIM# 619317; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3771 SMARCA5 Zornitza Stark gene: SMARCA5 was added
gene: SMARCA5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SMARCA5 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: SMARCA5 were set to 33980485
Phenotypes for gene: SMARCA5 were set to Neurodevelopmental disorder; microcephaly; dysmorphic features
Review for gene: SMARCA5 was set to GREEN
Added comment: 12 individuals reported with either de novo or appropriately segregating variants in this gene and mild developmental delay, frequent postnatal short stature and microcephaly, and recurrent dysmorphic features. Functional data supports gene-disease association.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3766 SPTAN1 Zornitza Stark Phenotypes for gene: SPTAN1 were changed from to Developmental and epileptic encephalopathy 5, MIM# 613477
Intellectual disability syndromic and non-syndromic v0.3763 SPTAN1 Zornitza Stark reviewed gene: SPTAN1: Rating: GREEN; Mode of pathogenicity: None; Publications: 20493457, 22258530, 32811770; Phenotypes: Developmental and epileptic encephalopathy 5, MIM# 613477; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3753 TMEM222 Konstantinos Varvagiannis gene: TMEM222 was added
gene: TMEM222 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TMEM222 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TMEM222 were set to 33824500
Phenotypes for gene: TMEM222 were set to Motor delay; Delayed speech and language development; Intellectual disability; Generalized hypotonia; Broad-based gait; Abnormality of nervous system morphology; Seizures; Microcephaly; Behavioral abnormality
Penetrance for gene: TMEM222 were set to Complete
Review for gene: TMEM222 was set to GREEN
Added comment: Polla et al (2021 - PMID: 33824500) report 17 individuals from 9 unrelated families, with biallelic TMEM222 pathogenic variants.

The phenotype included motor, speech delay and moderate to severe ID (as universal features). Other manifestations included hypotonia (10/15), broad gait (5/12), seizures (7/17 - belonging to 6/9 families), MRI abnormalities (5/8). Variable behavioral abnormalities were observed (aggressive behavior, shy character, stereotypic movements etc). Abnormal OFC was a feature in several with microcephaly in 7 subjects from 4 families (measurements not available for all 17). Nonspecific facial features were reported in 10/17. Rare features incl. body tremors, decreased lower extremity muscle mass or disorder of motor neurons.

TMEM222 variants were identified following exome sequencing. Previous investigations incl. metabolic studies, FMR1, chromosomes by standard karyotype or CMA, SMA, CMT1A were reported to be normal (available for some individuals).

TMEM222 variants missense and pLoF ones mostly found in homozygosity (7/9 families were consanguineous, compound heterozygosity reported in a single case from the 9 families). Sanger sequencing was used for confirmation of variants, parental carrier state as well as testing of sibs (unaffected sibs tested in 4 families).

Few individuals had additional genetic findings in other genes, though classified as VUS (3 families).

The gene encodes transmembrane protein 222 (208 residues) which however has unknown function. The protein comprises 3 transmembrane domains and a domain of unknown function. TMEMs are a group of transmembrane proteins spanning membranes with - most commonly - unclear function.

The authors measured expression by qPCR mRNA analysis, demonstrating highest fetal and adult brain expression (incl. parietal and occipital cortex). Expression levels from GTEx data also support a role in neurodevelopment.

Immunocytochemistry revealed highest levels in mature human iPSC-derived glutaminergic cortical neurons and moderate in immature ones. Additional studies supported that the gene is highly expressed in dendrites and might play a role in postsynaptic vesicles (colocalization with postsynaptic and early endosomal markers).

A previous study by Riazuddin et al (2017 - PMID: 27457812) had identified TMEM222 as a candidate gene for ID. This family (PKMR213) however appears to be included as family 2 in the aforementioned publication (same pedigree, variant and phenotype in both articles).

In OMIM there is currently no associated phenotype.

The gene is listed among the primary ID genes in SysID.

Please consider inclusion in the ID panel with green (or amber) rating. This gene may also be included in other panels e.g. for epilepsy, microcephaly, etc.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3737 YWHAG Zornitza Stark Phenotypes for gene: YWHAG were changed from to Developmental and epileptic encephalopathy 56, (MIMI#617665)
Intellectual disability syndromic and non-syndromic v0.3734 YWHAG Zornitza Stark reviewed gene: YWHAG: Rating: GREEN; Mode of pathogenicity: None; Publications: 33393734, 33590706, 31926053, 33767733; Phenotypes: Developmental and epileptic encephalopathy 56, (MIMI#617665); Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3733 MED25 Zornitza Stark Phenotypes for gene: MED25 were changed from to Basel-Vanagait-Smirin-Yosef syndrome, MIM# 616449; Congenital cataract-microcephaly-naevus flammeus syndrome MONDO:0014643
Intellectual disability syndromic and non-syndromic v0.3730 MED25 Zornitza Stark reviewed gene: MED25: Rating: GREEN; Mode of pathogenicity: None; Publications: 25792360, 32816121; Phenotypes: Basel-Vanagait-Smirin-Yosef syndrome, MIM# 616449, Congenital cataract-microcephaly-naevus flammeus syndrome MONDO:0014643; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3730 SIN3B Elena Savva gene: SIN3B was added
gene: SIN3B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SIN3B was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: SIN3B were set to PMID: 33811806
Phenotypes for gene: SIN3B were set to Syndromic intellectual disability/autism spectrum disorder
Review for gene: SIN3B was set to GREEN
Added comment: PMID: 33811806
- 9 affected patients, all de novo (2 PTCs, 2 missense, multigenic CNVs)
- syndrome hallmarked by intellectual disability, developmental delay, and dysmorphic facial features with variably penetrant ASD, congenital malformations, corpus callosum defects, and impaired growth.
- All SNV carriers had mild/mod ID
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3730 PPIL1 Zornitza Stark Phenotypes for gene: PPIL1 were changed from Pontocerebellar hypoplasia; microcephaly; seizures to Pontocerebellar hypoplasia, type 14, MIM# 619301; microcephaly; seizures
Intellectual disability syndromic and non-syndromic v0.3729 PPIL1 Zornitza Stark edited their review of gene: PPIL1: Changed phenotypes: Pontocerebellar hypoplasia, type 14, MIM# 619301, microcephaly, seizures
Intellectual disability syndromic and non-syndromic v0.3721 PPP2R5C Sue White gene: PPP2R5C was added
gene: PPP2R5C was added to Intellectual disability syndromic and non-syndromic. Sources: Research
Mode of inheritance for gene: PPP2R5C was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: PPP2R5C were set to macrocephaly; intellectual disability
Penetrance for gene: PPP2R5C were set to Complete
Review for gene: PPP2R5C was set to AMBER
Added comment: Emerging unpublished evidence of monoallelic missense variants causing intellectual disability and macrocephaly
Sources: Research
Intellectual disability syndromic and non-syndromic v0.3717 KCNJ6 Zornitza Stark changed review comment from: Keppen-Lubinsky syndrome characterised by severely delayed psychomotor development, hypertonia, hyperreflexia, generalized lipodystrophy giving an aged appearance, and distinctive dysmorphic features, including microcephaly, prominent eyes, narrow nasal bridge, and open mouth.

Three unrelated individuals reported with de novo variants in this gene (one recurred in 2), mouse model.; to: Keppen-Lubinsky syndrome characterised by severely delayed psychomotor development, hypertonia, hyperreflexia, generalized lipodystrophy giving an aged appearance, and distinctive dysmorphic features, including microcephaly, prominent eyes, narrow nasal bridge, and open mouth.

Four unrelated individuals reported with de novo variants in this gene (one recurred in 2), mouse model. One of the individuals did not have lipodystrophy but had a prominent hyperkinetic movement disorder.
Intellectual disability syndromic and non-syndromic v0.3705 TGIF1 Zornitza Stark Phenotypes for gene: TGIF1 were changed from to Holoprosencephaly 4, MIM# 142946; MONDO:0007734
Intellectual disability syndromic and non-syndromic v0.3702 TGIF1 Zornitza Stark reviewed gene: TGIF1: Rating: GREEN; Mode of pathogenicity: None; Publications: 10835638, 16323008; Phenotypes: Holoprosencephaly 4, MIM# 142946, MONDO:0007734; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3702 NEUROD2 Zornitza Stark Phenotypes for gene: NEUROD2 were changed from Epileptic encephalopathy, early infantile, 72, MIM# 618374 to Epileptic encephalopathy, early infantile, 72, MIM# 618374; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.3700 NEUROD2 Zornitza Stark gene: NEUROD2 was added
gene: NEUROD2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NEUROD2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: NEUROD2 were set to 33438828; 30323019
Phenotypes for gene: NEUROD2 were set to Epileptic encephalopathy, early infantile, 72, MIM# 618374
Review for gene: NEUROD2 was set to GREEN
Added comment: Four unrelated individuals altogether with de novo variants in this gene, two presenting predominantly with seizures, and two with ID.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3687 KCNH1 Zornitza Stark Phenotypes for gene: KCNH1 were changed from to Temple-Baraitser syndrome, OMIM:611816; Zimmermann-Laband syndrome 1, OMIM:135500; Intellectual disability; Encephalopathy without features of TBS/ZLS
Intellectual disability syndromic and non-syndromic v0.3684 KCNH1 Arina Puzriakova reviewed gene: KCNH1: Rating: GREEN; Mode of pathogenicity: None; Publications: 33811134; Phenotypes: Temple-Baraitser syndrome, OMIM:611816, Zimmermann-Laband syndrome 1, OMIM:135500, Intellectual disability, Encephalopathy without features of TBS/ZLS; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3679 PLCH1 Zornitza Stark gene: PLCH1 was added
gene: PLCH1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PLCH1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PLCH1 were set to 33820834
Phenotypes for gene: PLCH1 were set to Holoprosencephaly spectrum; Severe developmental delay; Brain malformations
Review for gene: PLCH1 was set to AMBER
Added comment: PMID: 33820834 (2021) - Two sibling pairs from two unrelated families with a holoprosencephaly spectrum phenotype and different homozygous PLCH1 variants (c.2065C>T, p.Arg689* and c.4235delA, p.Cys1079ValfsTer16, respectively). One family presented with congenital hydrocephalus, epilepsy, significant developmental delay and a monoventricle or fused thalami; while sibs from the second family had alobar holoprosencephaly and cyclopia. 3/4 individuals also displayed a cleft palate and congenital heart disease. Human embryo immunohistochemistry showed PLCH1 to be expressed in the notorcord, developing spinal cord (in a ventral to dorsal gradient), dorsal root ganglia, cerebellum and dermatomyosome.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3629 PIK3R2 Zornitza Stark Phenotypes for gene: PIK3R2 were changed from to Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1, MIM# 603387
Intellectual disability syndromic and non-syndromic v0.3626 PIK3R2 Zornitza Stark reviewed gene: PIK3R2: Rating: GREEN; Mode of pathogenicity: None; Publications: 22729224, 23745724, 33604570; Phenotypes: Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1, MIM# 603387; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3597 COPB1 Zornitza Stark Phenotypes for gene: COPB1 were changed from Severe intellectual disability; variable microcephaly; cataracts to Baralle-Macken syndrome, MIM# 619255; Severe intellectual disability; variable microcephaly; cataracts
Intellectual disability syndromic and non-syndromic v0.3596 COPB1 Zornitza Stark edited their review of gene: COPB1: Changed phenotypes: Baralle-Macken syndrome, MIM# 619255, Severe intellectual disability, variable microcephaly, cataracts
Intellectual disability syndromic and non-syndromic v0.3596 TTC5 Zornitza Stark Phenotypes for gene: TTC5 were changed from Central hypotonia; Global developmental delay; Intellectual disability; Abnormality of nervous system morphology; Microcephaly; Abnormality of the face; Behavioral abnormality; Abnormality of the genitourinary system to Neurodevelopmental disorder with cerebral atrophy and variable facial dysmorphism , MIM#619244; Central hypotonia; Global developmental delay; Intellectual disability; Abnormality of nervous system morphology; Microcephaly; Abnormality of the face; Behavioral abnormality; Abnormality of the genitourinary system
Intellectual disability syndromic and non-syndromic v0.3595 WDR62 Zornitza Stark Phenotypes for gene: WDR62 were changed from to Microcephaly 2, primary, autosomal recessive, with or without cortical malformations, MIM# 604317; MONDO:0011435
Intellectual disability syndromic and non-syndromic v0.3592 WDR62 Zornitza Stark reviewed gene: WDR62: Rating: GREEN; Mode of pathogenicity: None; Publications: 20890279, 20729831, 20890278, 21496009, 21834044, 22775483, 32677750, 31788460; Phenotypes: Microcephaly 2, primary, autosomal recessive, with or without cortical malformations, MIM# 604317, MONDO:0011435; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3592 TRMT10A Zornitza Stark Phenotypes for gene: TRMT10A were changed from to Microcephaly, short stature, and impaired glucose metabolism 1, MIM# 616033; MONDO:0000208
Intellectual disability syndromic and non-syndromic v0.3589 TRMT10A Zornitza Stark reviewed gene: TRMT10A: Rating: GREEN; Mode of pathogenicity: None; Publications: 24204302, 25053765, 33448213, 33067246, 26535115, 26526202, 26297882; Phenotypes: Microcephaly, short stature, and impaired glucose metabolism 1, MIM# 616033, MONDO:0000208; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3588 STIL Zornitza Stark Phenotypes for gene: STIL were changed from to Microcephaly 7, primary, autosomal recessive, MIM# 612703; MONDO:0012989
Intellectual disability syndromic and non-syndromic v0.3585 STIL Zornitza Stark reviewed gene: STIL: Rating: GREEN; Mode of pathogenicity: None; Publications: 19215732, 22989186, 25218063, 33132204, 32677750, 29230157; Phenotypes: Microcephaly 7, primary, autosomal recessive, MIM# 612703, MONDO:0012989; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3585 STAMBP Zornitza Stark Phenotypes for gene: STAMBP were changed from to Microcephaly-capillary malformation syndrome, MIM# 614261; MONDO:0013659
Intellectual disability syndromic and non-syndromic v0.3582 STAMBP Zornitza Stark reviewed gene: STAMBP: Rating: GREEN; Mode of pathogenicity: None; Publications: 23542699, 31638258, 29907875, 27531570, 25692795, 25266620; Phenotypes: Microcephaly-capillary malformation syndrome, MIM# 614261, MONDO:0013659; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3582 RTTN Zornitza Stark Phenotypes for gene: RTTN were changed from to Microcephaly, short stature, and polymicrogyria with seizures, MIM# 614833; Microcephalic primordial dwarfism due to RTTN deficiency MONDO:0018764
Intellectual disability syndromic and non-syndromic v0.3579 RTTN Zornitza Stark reviewed gene: RTTN: Rating: GREEN; Mode of pathogenicity: None; Publications: 22939636, 26608784, 26940245, 30121372, 29967526, 30927481, 30121372; Phenotypes: Microcephaly, short stature, and polymicrogyria with seizures, MIM# 614833, Microcephalic primordial dwarfism due to RTTN deficiency MONDO:0018764; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3578 NDE1 Zornitza Stark Phenotypes for gene: NDE1 were changed from to Lissencephaly 4 (with microcephaly), MIM# 614019; MONDO:0013527; Microhydranencephaly, MIM# 605013; MONDO:0011504
Intellectual disability syndromic and non-syndromic v0.3575 NDE1 Zornitza Stark reviewed gene: NDE1: Rating: GREEN; Mode of pathogenicity: None; Publications: 21529752, 21529751, 30637988, 15473967; Phenotypes: Lissencephaly 4 (with microcephaly), MIM# 614019, MONDO:0013527, Microhydranencephaly, MIM# 605013, MONDO:0011504; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3575 MSMO1 Zornitza Stark Phenotypes for gene: MSMO1 were changed from to Microcephaly, congenital cataract, and psoriasiform dermatitis, MIM# 616834; MONDO:0014793
Intellectual disability syndromic and non-syndromic v0.3572 MSMO1 Zornitza Stark reviewed gene: MSMO1: Rating: GREEN; Mode of pathogenicity: None; Publications: 27604308, 21285510, 24144731, 33161406, 28673550, 33161406; Phenotypes: Microcephaly, congenital cataract, and psoriasiform dermatitis, MIM# 616834, MONDO:0014793; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3572 MCPH1 Zornitza Stark Phenotypes for gene: MCPH1 were changed from to Microcephaly 1, primary, autosomal recessive, MIM# 251200; MONDO:0009617
Intellectual disability syndromic and non-syndromic v0.3569 MCPH1 Zornitza Stark reviewed gene: MCPH1: Rating: GREEN; Mode of pathogenicity: None; Publications: 12046007, 15199523, 16311745, 20978018, 32294449, 30351297, 29026105; Phenotypes: Microcephaly 1, primary, autosomal recessive, MIM# 251200, MONDO:0009617; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3569 LARP7 Zornitza Stark Phenotypes for gene: LARP7 were changed from to Alazami syndrome, MIM# 615071; Microcephalic primordial dwarfism, Alazami type MONDO:0014031
Intellectual disability syndromic and non-syndromic v0.3566 LARP7 Zornitza Stark reviewed gene: LARP7: Rating: GREEN; Mode of pathogenicity: None; Publications: 22865833, 21937992, 30006060, 33569879; Phenotypes: Alazami syndrome, MIM# 615071, Microcephalic primordial dwarfism, Alazami type MONDO:0014031; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3566 KNL1 Zornitza Stark Phenotypes for gene: KNL1 were changed from to Microcephaly 4, primary, autosomal recessive, MIM# 604321; MONDO:0011437
Intellectual disability syndromic and non-syndromic v0.3563 KNL1 Zornitza Stark reviewed gene: KNL1: Rating: GREEN; Mode of pathogenicity: None; Publications: 22983954, 26626498, 27149178, 30304678, 27784895; Phenotypes: Microcephaly 4, primary, autosomal recessive, MIM# 604321, MONDO:0011437; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3562 KIF11 Zornitza Stark Phenotypes for gene: KIF11 were changed from Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation, MIM# 152950; MONDO:0007918 to Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation, MIM# 152950; MONDO:0007918
Intellectual disability syndromic and non-syndromic v0.3561 KIF11 Zornitza Stark Phenotypes for gene: KIF11 were changed from Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation MIM#152950 to Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation, MIM# 152950; MONDO:0007918
Intellectual disability syndromic and non-syndromic v0.3559 KIF11 Zornitza Stark reviewed gene: KIF11: Rating: GREEN; Mode of pathogenicity: None; Publications: 22284827, 25115524, 25124931, 27212378, 32730767, 31993640, 25996076; Phenotypes: Microcephaly with or without chorioretinopathy, lymphoedema, or mental retardation, MIM# 152950, MONDO:0007918; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3559 IER3IP1 Zornitza Stark Phenotypes for gene: IER3IP1 were changed from to Microcephaly, epilepsy, and diabetes syndrome, MIM# 614231; Primary microcephaly-epilepsy-permanent neonatal diabetes syndrome, MONDO:0013647
Intellectual disability syndromic and non-syndromic v0.3556 IER3IP1 Zornitza Stark reviewed gene: IER3IP1: Rating: GREEN; Mode of pathogenicity: None; Publications: 21835305, 22991235, 24138066, 28711742; Phenotypes: Microcephaly, epilepsy, and diabetes syndrome, MIM# 614231, Primary microcephaly-epilepsy-permanent neonatal diabetes syndrome, MONDO:0013647; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3556 EFTUD2 Zornitza Stark Phenotypes for gene: EFTUD2 were changed from to Mandibulofacial dysostosis, Guion-Almeida type, MIM# 610536; Mandibulofacial dysostosis-microcephaly syndrome MONDO:0012516
Intellectual disability syndromic and non-syndromic v0.3553 EFTUD2 Zornitza Stark reviewed gene: EFTUD2: Rating: GREEN; Mode of pathogenicity: None; Publications: 22305528, 23188108, 33601405, 33262786, 26507355; Phenotypes: Mandibulofacial dysostosis, Guion-Almeida type, MIM# 610536, Mandibulofacial dysostosis-microcephaly syndrome MONDO:0012516; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3553 CEP152 Zornitza Stark Phenotypes for gene: CEP152 were changed from to Microcephaly 9, primary, autosomal recessive, MIM# 614852; MONDO:0013923; Seckel syndrome 5, MIM# 613823; MONDO:0013443
Intellectual disability syndromic and non-syndromic v0.3550 CEP152 Zornitza Stark reviewed gene: CEP152: Rating: GREEN; Mode of pathogenicity: None; Publications: 20598275, 22775483, 21131973, 23199753; Phenotypes: Microcephaly 9, primary, autosomal recessive, MIM# 614852, MONDO:0013923, Seckel syndrome 5, MIM# 613823, MONDO:0013443; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3539 SATB1 Zornitza Stark Phenotypes for gene: SATB1 were changed from Developmental delay with dysmorphic facies and dental anomalies, MIM# 619228; Neurodevelopmental disorder; intellectual disability; epilepsy; microcephaly to Kohlschutter-Tonz syndrome-like, MIM# 619229; Developmental delay with dysmorphic facies and dental anomalies, MIM# 619228; Neurodevelopmental disorder; intellectual disability; epilepsy; microcephaly
Intellectual disability syndromic and non-syndromic v0.3538 SATB1 Zornitza Stark edited their review of gene: SATB1: Added comment: Kohlschutter-Tonz syndrome-like (KTZSL) is characterized by global developmental delay with moderately to severely impaired intellectual development, poor or absent speech, and delayed motor skills. Although the severity of the disorder varies, many patients are nonverbal and have hypotonia with inability to sit or walk. Early-onset epilepsy is common and may be refractory to treatment, leading to epileptic encephalopathy and further interruption of developmental progress. Most patients have feeding difficulties with poor overall growth and dysmorphic facial features, as well as significant dental anomalies resembling amelogenesis imperfecta. This phenotype was reported in 28 patients (patients 13 to 40, PMID 33513338), including 9 patients from 3 families. Most variants were de novo, though some were inherited, suggestive of incomplete penetrance and variable expressivity.

Developmental delay with dysmorphic facies and dental anomalies (DEFDA) is characterized by generally mild global developmental delay with variably impaired intellectual development, walking by 2 to 3 years, and slow language acquisition. The severity of the disorder ranges from moderate cognitive deficits to mild learning difficulties or behavioral abnormalities. Most patients have dysmorphic facial features, often with abnormal dentition and nonspecific visual defects, such as myopia, astigmatism, and strabismus. Although rare, involvement of other systems, such as skeletal, cardiac, and gastrointestinal, may be present. 12 individuals from 11 families reported (one inherited variant, affected parent).; Changed phenotypes: Kohlschutter-Tonz syndrome-like, MIM# 619229, Developmental delay with dysmorphic facies and dental anomalies, MIM# 619228, Developmental disorders
Intellectual disability syndromic and non-syndromic v0.3538 SATB1 Zornitza Stark Phenotypes for gene: SATB1 were changed from Neurodevelopmental disorder; intellectual disability; epilepsy; microcephaly to Developmental delay with dysmorphic facies and dental anomalies, MIM# 619228; Neurodevelopmental disorder; intellectual disability; epilepsy; microcephaly
Intellectual disability syndromic and non-syndromic v0.3525 DOCK7 Zornitza Stark Phenotypes for gene: DOCK7 were changed from Developmental and epileptic encephalopathy 23 MIM#615859 to Developmental and epileptic encephalopathy 23 MIM#615859; MONDO:0014371
Intellectual disability syndromic and non-syndromic v0.3524 DOCK7 Zornitza Stark Phenotypes for gene: DOCK7 were changed from to Developmental and epileptic encephalopathy 23 MIM#615859
Intellectual disability syndromic and non-syndromic v0.3521 DOCK7 Paul De Fazio reviewed gene: DOCK7: Rating: GREEN; Mode of pathogenicity: None; Publications: 24814191, 30771731, 30807358; Phenotypes: Developmental and epileptic encephalopathy 23 MIM#615859; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.3520 COPB1 Zornitza Stark gene: COPB1 was added
gene: COPB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: COPB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: COPB1 were set to 33632302
Phenotypes for gene: COPB1 were set to Severe intellectual disability; variable microcephaly; cataracts
Review for gene: COPB1 was set to AMBER
Added comment: Two unrelated families, some supportive functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3519 SLC1A4 Zornitza Stark Phenotypes for gene: SLC1A4 were changed from Spastic tetraplegia, thin corpus callosum, and progressive microcephaly, MIM# 616657 to Spastic tetraplegia, thin corpus callosum, and progressive microcephaly, MIM# 616657; MONDO:0014725
Intellectual disability syndromic and non-syndromic v0.3488 CDK5RAP2 Zornitza Stark Phenotypes for gene: CDK5RAP2 were changed from to Microcephaly 3, primary, autosomal recessive, MIM# 604804; MONDO:0011488
Intellectual disability syndromic and non-syndromic v0.3485 CDK5RAP2 Zornitza Stark reviewed gene: CDK5RAP2: Rating: GREEN; Mode of pathogenicity: None; Publications: 15793586, 22887808, 23995685, 23726037, 27761245, 20460369, 32677750, 32015000; Phenotypes: Microcephaly 3, primary, autosomal recessive, MIM# 604804, MONDO:0011488; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3480 EEF2 Zornitza Stark gene: EEF2 was added
gene: EEF2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: EEF2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: EEF2 were set to 33355653
Phenotypes for gene: EEF2 were set to Neurodevelopmental disorder; macrocephaly; hydrocephalus
Review for gene: EEF2 was set to GREEN
Added comment: De novo EEF2 missense variants reported in 3 unrelated children (3, 6 and 9 years of age) with a mild neurodevelopmental phenotype comprising motor delay and relative macrocephaly associated with ventriculomegaly.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3474 EIF5A Zornitza Stark gene: EIF5A was added
gene: EIF5A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: EIF5A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: EIF5A were set to 33547280
Phenotypes for gene: EIF5A were set to Intellectual disability; microcephaly; dysmorphism
Review for gene: EIF5A was set to GREEN
Added comment: 7 unrelated individuals reported with de novo variants in this gene and variable combinations of developmental delay, microcephaly, micrognathia and dysmorphism.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3472 POLRMT Zornitza Stark gene: POLRMT was added
gene: POLRMT was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: POLRMT was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: POLRMT were set to 33602924
Phenotypes for gene: POLRMT were set to Mitochondrial disorder; intellectual disability; hypotonia
Review for gene: POLRMT was set to GREEN
Added comment: 8 individuals from 7 families reported. 5 families with bi-allelic variants and 2 with heterozygous variants. Affected individuals presented with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3471 KARS Zornitza Stark Phenotypes for gene: KARS were changed from Leukoencephalopathy with or without deafness (LEPID), MIM#619147; Combined mitochondrial oxidative phosphorylation deficiency; epilepsy; intellectual disability; microcephaly to Leukoencephalopathy with or without deafness (LEPID), MIM#619147; Combined mitochondrial oxidative phosphorylation deficiency; epilepsy; intellectual disability; microcephaly
Intellectual disability syndromic and non-syndromic v0.3471 KARS Zornitza Stark Phenotypes for gene: KARS were changed from Combined mitochondrial oxidative phosphorylation deficiency; epilepsy; intellectual disability; microcephaly to Leukoencephalopathy with or without deafness (LEPID), MIM#619147; Combined mitochondrial oxidative phosphorylation deficiency; epilepsy; intellectual disability; microcephaly
Intellectual disability syndromic and non-syndromic v0.3470 KARS Zornitza Stark edited their review of gene: KARS: Changed phenotypes: Leukoencephalopathy with or without deafness (LEPID), MIM#619147, Combined mitochondrial oxidative phosphorylation deficiency, epilepsy, intellectual disability, microcephaly
Intellectual disability syndromic and non-syndromic v0.3458 LMNB2 Zornitza Stark Phenotypes for gene: LMNB2 were changed from Congenital microcephaly; Global developmental delay; Intellectual disability to Microcephaly 27, primary, autosomal dominant, MIM# 619180; Congenital microcephaly; Global developmental delay; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.3457 LMNB2 Zornitza Stark reviewed gene: LMNB2: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Microcephaly 27, primary, autosomal dominant, MIM# 619180; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3457 LMNB1 Zornitza Stark Phenotypes for gene: LMNB1 were changed from Global developmental delay, Intellectual disability, Microcephaly, Short stature, Seizures, Abnormality of the corpus callosum, Cortical gyral simplification, Feeding difficulties, Scoliosis; Leukodystrophy, adult-onset, autosomal dominant, MIM#169500 to Microcephaly 26, primary, autosomal dominant, MIM# 619179; Global developmental delay, Intellectual disability, Microcephaly, Short stature, Seizures, Abnormality of the corpus callosum, Cortical gyral simplification, Feeding difficulties, Scoliosis; Leukodystrophy, adult-onset, autosomal dominant, MIM#169500
Intellectual disability syndromic and non-syndromic v0.3456 FGF13 Zornitza Stark Phenotypes for gene: FGF13 were changed from Intellectual disability; epilepsy to Developmental and epileptic encephalopathy 90, MIM# 301058; Intellectual disability; epilepsy
Intellectual disability syndromic and non-syndromic v0.3455 FGF13 Zornitza Stark edited their review of gene: FGF13: Changed phenotypes: Developmental and epileptic encephalopathy 90, MIM# 301058, Intellectual disability, epilepsy
Intellectual disability syndromic and non-syndromic v0.3452 MSL3 Zornitza Stark commented on gene: MSL3: Well established ID gene. 2021 paper documents findings in 25 individuals. Variants found to be clustering in the terminal eight exons suggesting that truncating variants in the first five exons might be compensated by an alternative MSL3 transcript. Three-dimensional modeling of missense and splice variants indicated that these have a deleterious effect. The main clinical findings comprised developmental delay and intellectual disability ranging from mild to severe. Autism spectrum disorder, muscle tone abnormalities, and macrocephaly were common as well as hearing impairment and gastrointestinal problems. Hypoplasia of the cerebellar vermis emerged as a consistent magnetic resonance image (MRI) finding.
Intellectual disability syndromic and non-syndromic v0.3439 OTUD5 Zornitza Stark Phenotypes for gene: OTUD5 were changed from X-linked severe neurodevelopmental delay, hydrocephalus, and early lethality to Multiple congenital anomalies-neurodevelopmental syndrome, X-linked, MIM# 301056
Intellectual disability syndromic and non-syndromic v0.3433 PRUNE1 Zornitza Stark Phenotypes for gene: PRUNE1 were changed from to Neurodevelopmental disorder with microcephaly, hypotonia, and variable brain anomalies , MIM#617481
Intellectual disability syndromic and non-syndromic v0.3430 PRUNE1 Zornitza Stark reviewed gene: PRUNE1: Rating: GREEN; Mode of pathogenicity: None; Publications: 26539891, 28334956, 33105479; Phenotypes: Neurodevelopmental disorder with microcephaly, hypotonia, and variable brain anomalies , MIM#617481; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3426 HIRA Paul De Fazio gene: HIRA was added
gene: HIRA was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HIRA was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: HIRA were set to 33417013; 28135719; 25363760
Phenotypes for gene: HIRA were set to Neurodevelopmental disorder
Review for gene: HIRA was set to GREEN
gene: HIRA was marked as current diagnostic
Added comment: Two unrelated patients with different de novo loss of function variants identified in PMID 33417013:

Individual 1: intragenic deletion, phenotype included psychomotor retardation, ID, growth retardation, microcephaly, and facial features reminiscent of 22q deletion syndrome.
Individual 2: canonical splice variant, phenotype mostly confined to ASD

Another two de novo variants were identified in the literature by the authors of that paper, one stop-gain (DDD study, PMID 28135719) and one missense (large autism cohort, PMID 25363760).

PMID 33417013 also showed that HIRA knockdown in mice results in neurodevelopmental abnormalities.

Rated Green due to 4 unrelated individuals (albeit 2 in large cohort studies) and a mouse model. NB: HIRA is within the common 22q deletion region.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3425 SATB1 Zornitza Stark Phenotypes for gene: SATB1 were changed from Developmental disorders to Neurodevelopmental disorder; intellectual disability; epilepsy; microcephaly
Intellectual disability syndromic and non-syndromic v0.3420 KCNN2 Ain Roesley gene: KCNN2 was added
gene: KCNN2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: KCNN2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: KCNN2 were set to 33242881
Phenotypes for gene: KCNN2 were set to neurodevelopmental movement disorders
Penetrance for gene: KCNN2 were set to unknown
Review for gene: KCNN2 was set to GREEN
Added comment: - 11 probands all de novo except for 1 mother-daughter pair.
- a mix of null and missense variants
- 2/11 with microcephaly, 10/11 motor delay, 7/11 language delay (excluding 2 with regression), all with varying degrees of ID, 3/11 seizures, 7/11 movement disorder, 4/11 cerebellar ataxia, 6/11 MRI anomalies

additional variants were noted in 2 patients: 1x cHet for variants in MED12L and 1x de novo TNK2 variant

patch clamp functional studies were also done
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3420 OTUD5 Chirag Patel gene: OTUD5 was added
gene: OTUD5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: OTUD5 was set to X-LINKED: hemizygous mutation in males, biallelic mutations in females
Publications for gene: OTUD5 were set to PMID: 33131077
Phenotypes for gene: OTUD5 were set to X-linked severe neurodevelopmental delay, hydrocephalus, and early lethality
Review for gene: OTUD5 was set to RED
Added comment: 13 male patients from a single family with three generations affected. Patients presented prenatally or during the neonatal period with IUGR, ventriculomegaly, hydrocephalus, hypotonia, congenital heart defects, hypospadias, and severe neurodevelopmental delay. The disease is typically fatal during infancy, mainly due to sepsis (pneumonias). Female carriers are asymptomatic. WGS in four individuals identified a unique candidate variant in the OTUD5 gene (NM_017602.3:c.598G > A, p.Glu200Lys). The variant cosegregated with the disease in 10 tested individuals. No functional studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3406 HNRNPU Zornitza Stark Phenotypes for gene: HNRNPU were changed from Epileptic encephalopathy, early infantile, 54, MIM#617391 to Developmental and epileptic encephalopathy 54 MIM# 617391
Intellectual disability syndromic and non-syndromic v0.3400 LAMB1 Zornitza Stark Phenotypes for gene: LAMB1 were changed from to Lissencephaly 5, MIM# 615191; Cystic leukoencephalopathy
Intellectual disability syndromic and non-syndromic v0.3397 LAMB1 Zornitza Stark reviewed gene: LAMB1: Rating: GREEN; Mode of pathogenicity: None; Publications: 23472759, 25925986, 29888467, 25925986; Phenotypes: Lissencephaly 5, MIM# 615191, Cystic leukoencephalopathy; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3384 SCAMP5 Zornitza Stark edited their review of gene: SCAMP5: Added comment: PMID 33390987: Four unrelated individuals reported with same de novo missense variant, p. Gly180Trp. The onset age of seizures was ranged from 6 to 15 months. Patients had different types of seizures, including focal seizures, generalized tonic-clonic seizures and tonic seizure. One patient showed typical autism spectrum disorder (ASD) symptoms. Electroencephalogram (EEG) findings presented as focal or multifocal discharges, sometimes spreading to generalization. Brain magnetic resonance imaging (MRI) abnormalities were present in each patient. Severe intellectual disability and language and motor developmental disorders were found in our patients, with all patients having poor language development and were nonverbal at last follow-up. All but one of the patients could walk independently in childhood, but the ability to walk independently in one patient had deteriorated with age. All patients had abnormal neurological exam findings, mostly signs of extrapyramidal system involvement. Dysmorphic features were found in 2/4 patients, mainly in the face and trunk.; Changed rating: GREEN; Changed publications: 33390987; Changed phenotypes: Intellectual disability, seizures, autism; Changed mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3383 ZNF526 Zornitza Stark gene: ZNF526 was added
gene: ZNF526 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZNF526 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ZNF526 were set to 21937992; 25558065; 33397746
Phenotypes for gene: ZNF526 were set to Intellectual disability; Microcephaly; Cataracts; Epilepsy; Hypertonia; Dystonia
Review for gene: ZNF526 was set to GREEN
Added comment: Currently not associated with any phenotype in OMIM (last updated on 09/12/2011), but has a 'possible' disease confidence rating for 'Autosomal Recessive Mental Retardation' in Gene2Phenotype.

- PMID: 21937992 (2011) - Two unrelated families (with 4 affected individuals in each) with non-syndromic ID (mild or moderate, respectively) identified harbouring different biallelic missense variants in the ZNF526 gene.

- PMID: 25558065 (2015) - One family with ID, Noonan-like facies, pulmonary stenosis and a homozygous missense variant in this gene. No further details provided.

- PMID: 33397746 (2021) - Five individuals from four unrelated families with homozygous ZNF526 variants. Four harboured truncating variants, and were all affected by profound DD and severe ID, microcephaly (ranging from -4 SD to -8 SD), bilateral progressive cataracts, hypertonic-dystonic movements, epilepsy and brain MRI anomalies. The fifth patient had a homozygous missense variant and a slightly less severe disorder, with postnatal microcephaly (-2 SD), progressive bilateral cataracts, severe ID, and normal brain MRI. Zebrafish model demonstrated brain and eye malformations resembling findings seen in the human holoprosencephaly spectrum
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3380 CELF2 Zornitza Stark gene: CELF2 was added
gene: CELF2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CELF2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CELF2 were set to 33131106
Phenotypes for gene: CELF2 were set to Developmental and epileptic encephalopathy
Review for gene: CELF2 was set to GREEN
Added comment: Five unrelated individuals reported. Four with de novo variants, and one inherited from a mosaic mother. Notably, all identified variants, except for c.272‐1G>C, were clustered within 20 amino acid residues of the C‐terminus, which might be a nuclear localization signal.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3367 DPH2 Paul De Fazio gene: DPH2 was added
gene: DPH2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: DPH2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DPH2 were set to 32576952; 27421267
Phenotypes for gene: DPH2 were set to Diphthamide-deficiency syndrome
Review for gene: DPH2 was set to AMBER
gene: DPH2 was marked as current diagnostic
Added comment: One 19 month old reported (PMID:32576952) with biallelic (one missense, one nonsense) variants in DPH2, with phenotype similar to DPH1 deficiency (gross motor delay, not walking, fine motor and expressive language delays, macrocephaly)

Another family (sibs) was previously reported with biallelic nonsense variants (PMID:27421267) with a comparable phenotype, this family also has biallelic variants in KALRN and the authors thought those variants more likely causative. Patients had ID and microcephaly (in contrast to the 19 month old above).

In vitro functional assays support reduced diphthamide synthesis activity for the variants identified in PMID:32576952.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3367 FBRSL1 Elena Savva gene: FBRSL1 was added
gene: FBRSL1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FBRSL1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: FBRSL1 were set to PMID: 32424618
Phenotypes for gene: FBRSL1 were set to Malformation and intellectual disability syndrome
Review for gene: FBRSL1 was set to GREEN
Added comment: Three children with de novo PTCs that escape NMD, and an overlapping syndromic phenotype with respiratory insufficiency, postnatal growth restriction, microcephaly, global developmental delay and other malformations. 2/3 had heart defects, cleft palate and hearing impairement.
Supported by Xenopus oocyte functional studies
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3360 YIF1B Zornitza Stark Phenotypes for gene: YIF1B were changed from Central hypotonia; Failure to thrive; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Spasticity; Abnormality of movement to Kaya-Barakat-Masson syndrome, MIM# 619125; Central hypotonia; Failure to thrive; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Spasticity; Abnormality of movement
Intellectual disability syndromic and non-syndromic v0.3359 YIF1B Zornitza Stark reviewed gene: YIF1B: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Kaya-Barakat-Masson syndrome, MIM# 619125, Central hypotonia, Failure to thrive, Microcephaly, Global developmental delay, Intellectual disability, Seizures, Spasticity, Abnormality of movement; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3356 SOX2 Zornitza Stark Phenotypes for gene: SOX2 were changed from Microphthalmia, syndromic 3, MIM# 206900; Optic nerve hypoplasia and abnormalities of the central nervous system, MIM# 206900 to Microphthalmia, syndromic 3, MIM# 206900; Optic nerve hypoplasia and abnormalities of the central nervous system, MIM# 206900
Intellectual disability syndromic and non-syndromic v0.3356 SOX2 Zornitza Stark Phenotypes for gene: SOX2 were changed from to Microphthalmia, syndromic 3, MIM# 206900; Optic nerve hypoplasia and abnormalities of the central nervous system, MIM# 206900
Intellectual disability syndromic and non-syndromic v0.3353 SOX2 Zornitza Stark reviewed gene: SOX2: Rating: GREEN; Mode of pathogenicity: None; Publications: 30450772, 28121235, 25542770, 24498598, 24211324, 24033328, 21326281; Phenotypes: Microphthalmia, syndromic 3, MIM# 206900, Optic nerve hypoplasia and abnormalities of the central nervous system, MIM# 206900; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3350 RARB Zornitza Stark Phenotypes for gene: RARB were changed from to Microphthalmia, syndromic 12, MIM# 615524
Intellectual disability syndromic and non-syndromic v0.3347 RARB Zornitza Stark reviewed gene: RARB: Rating: GREEN; Mode of pathogenicity: None; Publications: 30880327, 30281527, 24075189, 27120018, 25457163, 17506106; Phenotypes: Microphthalmia, syndromic 12, MIM# 615524; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3347 SMOC1 Zornitza Stark Phenotypes for gene: SMOC1 were changed from to Microphthalmia with limb anomalies, MIM# 206920
Intellectual disability syndromic and non-syndromic v0.3344 SMOC1 Zornitza Stark reviewed gene: SMOC1: Rating: GREEN; Mode of pathogenicity: None; Publications: 21194678, 21194680, 30445150; Phenotypes: Microphthalmia with limb anomalies, MIM# 206920; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3344 MAB21L2 Zornitza Stark Phenotypes for gene: MAB21L2 were changed from to Microphthalmia/coloboma and skeletal dysplasia syndrome, MIM# 615877
Intellectual disability syndromic and non-syndromic v0.3341 MAB21L2 Zornitza Stark reviewed gene: MAB21L2: Rating: GREEN; Mode of pathogenicity: None; Publications: 24906020, 25719200, 31037784, 30375740, 30073347, 26116559; Phenotypes: Microphthalmia/coloboma and skeletal dysplasia syndrome, MIM# 615877; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3337 GAD1 Zornitza Stark Phenotypes for gene: GAD1 were changed from Cerebral palsy, spastic quadriplegic, 1, MIM#603513; Developmental and epileptic encephalopathy to Cerebral palsy, spastic quadriplegic, 1, MIM#603513; Developmental and epileptic encephalopathy 89, MIM# 619124
Intellectual disability syndromic and non-syndromic v0.3336 GAD1 Zornitza Stark edited their review of gene: GAD1: Changed phenotypes: Cerebral palsy, spastic quadriplegic, 1, MIM#603513, Developmental and epileptic encephalopathy 89, MIM# 619124
Intellectual disability syndromic and non-syndromic v0.3275 SHMT2 Zornitza Stark Phenotypes for gene: SHMT2 were changed from Congenital microcephaly; Infantile axial hypotonia; Spastic paraparesis; Global developmental delay; Intellectual disability; Abnormality of the corpus callosum; Abnormal cortical gyration; Hypertrophic cardiomyopathy; Abnormality of the face; Proximal placement of thumb; 2-3 toe syndactyly to Neurodevelopmental disorder with cardiomyopathy, spasticity, and brain abnormalities (NEDCASB), MIM#619121; Congenital microcephaly; Infantile axial hypotonia; Spastic paraparesis; Global developmental delay; Intellectual disability; Abnormality of the corpus callosum; Abnormal cortical gyration; Hypertrophic cardiomyopathy; Abnormality of the face; Proximal placement of thumb; 2-3 toe syndactyly
Intellectual disability syndromic and non-syndromic v0.3274 SHMT2 Zornitza Stark reviewed gene: SHMT2: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with cardiomyopathy, spasticity, and brain abnormalities (NEDCASB), MIM#619121, Congenital microcephaly, Infantile axial hypotonia, Spastic paraparesis, Global developmental delay, Intellectual disability, Abnormality of the corpus callosum, Abnormal cortical gyration, Hypertrophic cardiomyopathy, Abnormality of the face, Proximal placement of thumb, 2-3 toe syndactylyCongenital microcephaly, Infantile axial hypotonia, Spastic paraparesis, Global developmental delay, Intellectual disability, Abnormality of the corpus callosum, Abnormal cortical gyration, Hypertrophic cardiomyopathy, Abnormality of the face, Proximal placement of thumb, 2-3 toe syndactyly; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3273 PPIL1 Zornitza Stark gene: PPIL1 was added
gene: PPIL1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PPIL1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PPIL1 were set to 33220177
Phenotypes for gene: PPIL1 were set to Pontocerebellar hypoplasia; microcephaly; seizures
Review for gene: PPIL1 was set to GREEN
Added comment: 17 individuals from 9 unrelated families reported with bi-allelic variants in the gene and PCH, microcephaly, hypotonia, seizures, severe DD/ID. Mouse models support gene-disease association.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3264 RAP1B Chirag Patel gene: RAP1B was added
gene: RAP1B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: RAP1B was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RAP1B were set to PMID: 32627184
Phenotypes for gene: RAP1B were set to RAP1B‐associated phenotype, no OMIM #
Review for gene: RAP1B was set to RED
Added comment: De novo variants in the RAP1B gene (c.35G>T p.(Gly12Val) and c.178G>C p.(Gly60Arg)) in two unrelated patients with thrombocytopenia, microcephaly, learning difficulties, renal malformations, structural anomalies of the brain and other features (not Kabuki like).

RAP1B is a member of the RAS superfamily of small GTPases. There is strong evidence that the p.Gly12Val and p.Gly60Arg variants in the RAP1B gene lead into a dysregulation of the downstream pathway. Both substitutions have been described previously as dominant constitutively active in RAS‐related proteins (gain of function variants).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3262 FBXO28 Zornitza Stark changed review comment from: Nine new individuals with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and all 10 known cases reviewed to delineate the phenotypic spectrum. All patients had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features.
Sources: Literature; to: Nine new individuals with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and all 10 known cases reviewed to delineate the phenotypic spectrum. All had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3261 FBXO28 Zornitza Stark gene: FBXO28 was added
gene: FBXO28 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FBXO28 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: FBXO28 were set to 33280099
Phenotypes for gene: FBXO28 were set to Developmental and epileptic encephalopathy
Review for gene: FBXO28 was set to GREEN
Added comment: Nine new individuals with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and all 10 known cases reviewed to delineate the phenotypic spectrum. All patients had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3251 VPS4A Elena Savva changed review comment from: Comment when marking as ready: PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain. 1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance). Demonstrated defective CD71 trafficking in all 3 patients. PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly). Demonstrated that the variants had a dominant-negative effect on VPS4A function. "The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."; to: PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain. 1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance). Demonstrated defective CD71 trafficking in all 3 patients.

PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly). Demonstrated that the variants had a dominant-negative effect on VPS4A function. "The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."
Intellectual disability syndromic and non-syndromic v0.3251 VPS4A Elena Savva Added comment: Comment when marking as ready: PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain. 1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance). Demonstrated defective CD71 trafficking in all 3 patients. PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly). Demonstrated that the variants had a dominant-negative effect on VPS4A function. "The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."
Intellectual disability syndromic and non-syndromic v0.3250 VPS4A Kristin Rigbye gene: VPS4A was added
gene: VPS4A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: VPS4A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: VPS4A were set to 33186543; 33186545
Phenotypes for gene: VPS4A were set to Neurodevelopmental disorder
Review for gene: VPS4A was set to GREEN
Added comment: PMID: 33186543 - 2x de novo hetorozygous missense variants in the AAA (large ATPase) domain.
1x homozygous missense in the MIT domain (milder phenotype and unaffected parents - possibly just a simple LoF mechanism for AR inheritance).
Demonstrated defective CD71 trafficking in all 3 patients.

PMID: 33186545 - 6x probands with de novo missense variants in the AAA domain. 5 of the variants were at amino acid position 284 (changes to Trp and Gly).
Demonstrated that the variants had a dominant-negative effect on VPS4A function.

"The six probands with de novo substitutions affecting Glu206 or Arg284 had a consistent phenotype characterized by severe DD, profound ID, and dystonia. Children were very delayed in establishing head control and none achieved independent walking. Other common findings were cerebellar hypoplasia (five individuals out of six, the other showing uncharacterized severe cerebral atrophy) with a variable degree of corpus callosum hypoplasia. One individual also had bilateral polymicrogyria. Epilepsy was present in three and dystonia in five subjects. Eye involvement was also a common finding, including congenital cataract, retinal dystrophy, and in one case congenital Leber amaurosis. Four individuals were diagnosed with hepatosplenomegaly and/or steatosis. Three subjects had anemia, which was characterized as dyserythropoietic in two. Severe feeding difficulties were present in four individuals, requiring assisted feeding in three. Two had sensorineural deafness. Severe growth retardation, generally for all parameters, was present in most cases. Notably, severe microcephaly (typically with Z scores < −5) was universal. Overall, the disorder seems to have a poor prognosis as two affected individuals died in childhood or early adult life."
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3248 KDM4B Kristin Rigbye gene: KDM4B was added
gene: KDM4B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: KDM4B was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: KDM4B were set to PMID: 33232677
Phenotypes for gene: KDM4B were set to Global developmental delay, intellectual disability and neuroanatomical defects
Review for gene: KDM4B was set to GREEN
Added comment: Nine individuals with mono-allelic de novo or inherited variants in KDM4B.

All individuals presented with dysmorphic features and global developmental delay (GDD) with language and motor skills most affected. Three individuals had a history of seizures, and four had anomalies on brain imaging ranging from agenesis of the corpus callosum with hydrocephalus to cystic formations, abnormal hippocampi, and polymicrogyria.

In a knockout mouse the total brain volume was significantly reduced with decreased
size of the hippocampal dentate gyrus, partial agenesis of the corpus callosum, and ventriculomegaly.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3245 KAT5 Zornitza Stark Phenotypes for gene: KAT5 were changed from Severe global developmental delay; Intellectual disability; Seizures; Microcephaly; Behavioral abnormality; Sleep disturbance; Morphological abnormality of the central nervous system; Short stature; Oral cleft; Abnormality of the face to Neurodevelopmental disorder with dysmorphic facies, sleep disturbance, and brain abnormalities (NEDFASB), MIM#619103; Severe global developmental delay; Intellectual disability; Seizures; Microcephaly; Behavioral abnormality; Sleep disturbance; Morphological abnormality of the central nervous system; Short stature; Oral cleft; Abnormality of the face
Intellectual disability syndromic and non-syndromic v0.3226 PIGB Zornitza Stark Phenotypes for gene: PIGB were changed from Epileptic encephalopathy, early infantile, 80; OMIM #618580 to Developmental and epileptic encephalopathy 80, MIM# 618580
Intellectual disability syndromic and non-syndromic v0.3225 PIGB Zornitza Stark reviewed gene: PIGB: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Developmental and epileptic encephalopathy 80, MIM# 618580; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3198 NARS Zornitza Stark Phenotypes for gene: NARS were changed from Neurodevelopmental disorder with microcephaly, impaired language, and gait abnormalities (NEDMILG), MIM#619091; Neurodevelopmental disorder with microcephaly, impaired language, epilepsy, and gait abnormalities (NEDMILEG), MIM#619092; Abnormal muscle tone; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Ataxia; Abnormality of the face; Demyelinating peripheral neuropathy to Neurodevelopmental disorder with microcephaly, impaired language, and gait abnormalities (NEDMILG), MIM#619091; Neurodevelopmental disorder with microcephaly, impaired language, epilepsy, and gait abnormalities (NEDMILEG), MIM#619092; Abnormal muscle tone; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Ataxia; Abnormality of the face; Demyelinating peripheral neuropathy
Intellectual disability syndromic and non-syndromic v0.3197 NARS Zornitza Stark Phenotypes for gene: NARS were changed from Abnormal muscle tone; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Ataxia; Abnormality of the face; Demyelinating peripheral neuropathy to Neurodevelopmental disorder with microcephaly, impaired language, and gait abnormalities (NEDMILG), MIM#619091; Neurodevelopmental disorder with microcephaly, impaired language, epilepsy, and gait abnormalities (NEDMILEG), MIM#619092; Abnormal muscle tone; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Ataxia; Abnormality of the face; Demyelinating peripheral neuropathy
Intellectual disability syndromic and non-syndromic v0.3196 NARS Zornitza Stark reviewed gene: NARS: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with microcephaly, impaired language, and gait abnormalities (NEDMILG), MIM#619091, Neurodevelopmental disorder with microcephaly, impaired language, epilepsy, and gait abnormalities (NEDMILEG), MIM#619092, Abnormal muscle tone, Microcephaly, Global developmental delay, Intellectual disability, Seizures, Ataxia, Abnormality of the face, Demyelinating peripheral neuropathy; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3173 ZFHX4 Zornitza Stark gene: ZFHX4 was added
gene: ZFHX4 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZFHX4 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ZFHX4 were set to 33057194; 24038936; 21802062
Phenotypes for gene: ZFHX4 were set to Developmental disorders; intellectual disability, dysmorphic features
Review for gene: ZFHX4 was set to GREEN
Added comment: PMID: 33057194 - Has been identified as a gene with significant de novo enrichment in a large trio study from the Deciphering Developmental Disorders study. 16 de novo variants (5 frameshift, 5 missense, 4 stopgain, 2 synonymous) identified in ~10,000 cases with developmental disorders (no other phenotype info provided).
PMID: 24038936 - a single case with developmental delay, macrocephaly, ventriculomegaly, hypermetropia, recurrent infections, dysmorphism and a de novo deletion of the last 7 exons of the gene.
PMID:21802062 (2011) report 8 individuals with ID and overlapping deletions of 8q21.11 (0.66-13.55 Mb in size); the smallest region of overlap encompasses 3 genes including ZFHX4.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3139 FOXP4 Zornitza Stark changed review comment from: Eight unrelated individuals reported, seven de novo missense, and one individual with a truncating variant. Detailed phenotypic information available on 6. Overlapping features included speech and language delays, growth abnormalities, congenital diaphragmatic hernia (2/6), cervical spine abnormalities, and ptosis. Intellectual disability described as mild in 2, some had normal intellect despite the early challenges.
Sources: Literature; to: Eight unrelated individuals reported, seven de novo missense, and one individual with a truncating variant. Detailed phenotypic information available on 6. Overlapping features included speech and language delays, growth abnormalities, congenital diaphragmatic hernia (2/6), cervical spine abnormalities, and ptosis. Intellectual disability described as mild in 2, some had normal intellect despite the early speech and language delays.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3139 FOXP4 Zornitza Stark changed review comment from: Six unrelated individuals reported, 5 with missense variants in the forkhead box DNA-binding domain of FOXP4, and one individual with a truncating variant. Overlapping features included speech and language delays, growth abnormalities, congenital diaphragmatic hernia, cervical spine abnormalities, and ptosis.
Sources: Literature; to: Eight unrelated individuals reported, seven de novo missense, and one individual with a truncating variant. Detailed phenotypic information available on 6. Overlapping features included speech and language delays, growth abnormalities, congenital diaphragmatic hernia (2/6), cervical spine abnormalities, and ptosis. Intellectual disability described as mild in 2, some had normal intellect despite the early challenges.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3128 PRKAR1B Konstantinos Varvagiannis gene: PRKAR1B was added
gene: PRKAR1B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PRKAR1B was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: PRKAR1B were set to https://doi.org/10.1101/2020.09.10.20190314; 33057194
Phenotypes for gene: PRKAR1B were set to Global developmental delay; Intellectual disability; Autism; Attention deficit hyperactivity disorder; Aggressive behavior; Abnormality of movement; Upslanted palpebral fissure
Penetrance for gene: PRKAR1B were set to unknown
Review for gene: PRKAR1B was set to AMBER
Added comment: Please consider inclusion of this gene with amber rating pending publication of the preprint and/or additional evidence.

Marbach et al. (2020 - medRxiv : https://doi.org/10.1101/2020.09.10.20190314 - last author : C. Schaaf) report 6 unrelated individuals with heterozygous missense PRKAR1B variants.

All presented formal ASD diagnosis (6/6), global developmental delay (6/6) and intellectual disability (all - formal evaluations were lacking though). Additional features included neurologic anomalies (movement disorders : dyspraxia, apraxia, clumsiness in all, with tremor/dystonia or involuntary movements as single occurrences). Three displayed high pain tolerance. Regression in speech was a feature in two. Additional behavior anomalies included ADHD (4-5/6) or aggression (3/6). There was no consistent pattern of malformations, physical anomalies or facial features (with the exception of uplsanted palpebral fissures reported in 4).

3 different missense variants were identified (NM_00116470:c.1003C>T - p.Arg335Trp, c.586G>A - p.Glu196Lys, c.500_501delAAinsTT - p.Gln167Leu) with Arg355Trp being a recurrent one within this cohort (4/6 subjects). A possible splicing effect may apply for the MNV. All variants are absent from gnomAD and the SNVs had CADD scores > 24.

In all cases were parental samples were available (5/6), the variant had occurred as a de novo event.

Protein kinase A (PKA) is a tetrameric holoenzyme formed by the association of 2 catalytic (C) subunits with a regulatory (R) subunit dimer. Activation of PKA is achieved through binding of 2 cAMP molecules to each R-subunit, and unleashing(/dissociation) of C-subunits to engage substrates. PRKACA/B genes encode the Cα- and Cβ-subunits while the 4 functionally non-redundant regulatory subunits are encoded by PRKAR1A/1B/2A/2B genes. As the authors comment, the RIβ subunit is primarily expressed in brain with higher expression in cortex and hypothalamus.

The functional consequences of the variants at cellular level were not studied.

Previous studies have demonstrated that downregulation of RIβ in murine hippocampal cultures, reduced phosphorylation of CREB, a transcription factor involved in long-term memory formation. The authors speculate that a similar effect on cAMP/PKA/CREB cascade may mediate the cognitive effects in humans. RIβ deficient mice also display diminished nociceptive pain, similar to the human phenotype. [Several refs provided].

The authors cite the study by Kaplanis et al (2020 - PMID: 33057194), where in a large sample of 31,058 trio exomes of children with developmental disorders, PRKAR1B was among the genes with significant enrichment for de novo missense variants. [The gene has a pLI score of 0.18 in gnomAD / o/e = 0.26 - so pLoF variants may not be deleterious].

Please note that a specific PRKAR1B variant (NM_002735.2:c.149T>G - p.Leu50Arg) has been previous reported to segregate with a late-onset neurodegenerative disorder characterized by dementia and/or parkinsonism within a large pedigree with 12 affected individuals [Wong et al 2014 - PMID: 25414040].
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3127 MPP5 Konstantinos Varvagiannis gene: MPP5 was added
gene: MPP5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MPP5 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: MPP5 were set to 33073849
Phenotypes for gene: MPP5 were set to Global developmental delay; Intellectual disability; Delayed speech and language development; Developmental regression; Behavioral abnormality
Penetrance for gene: MPP5 were set to unknown
Review for gene: MPP5 was set to GREEN
Added comment: Sterling et al (2020 - PMID: 33073849) provide information on the phenotype of 3 individuals with de novo MPP5 variants.

Common features included global developmental delay, intellectual disability (3/3 - severe in 2/3), speech delay/regression (the latter in at least 2) and behavioral abnormalities. Variable other features were reported, among others microcephaly (1/3), abnormal vision (1/3 : CVI, retinal dystrophy, nystagmus), brain MRI abnormalities (2/3), late-onset seizures (1/3). These subjects displayed variable and non-specific dysmorphic features.

All were investigated by exome sequencing (previous investigations not mentioned).

One subject was found to harbor a de novo mosaic (5/25 reads) stopgain variant, further confirmed by Sanger sequencing [NM_022474.4:c.1555C>T - p.(Arg519Ter). The specific variant is reported once in gnomAD (1/251338). Two de novo missense variants were identified in the remaining individuals [c.1289A>G - p.Glu430Gly / c.974A>C - p.His325Pro). All variants had in silico predictions in favor of a deleterious effect (CADD score >24).

The authors comment that MPP5 encodes an apical complex protein with asymmetric localization to the apical side of polarized cells. It is expressed in brain, peripheral nervous system and other tissues. MPP5 is a member of the membrane-associated guanylate kinase family of proteins (MAGUK p55 subfamily), determining cell polarity at tight junctions.

Previous animal models suggest that complete Mpp5(Pals1) KO in mice leads to near absence of cerebral cortical neurons. Htz KO display reduction in size of cerebral cortex and hippocampus. The gene is expressed in proliferating cell populations of cerebellum and important for establishment cerebellar architecture. Conditional KO of Mpp5(Pals1) in retinal progenitor cells mimics the retinal pathology observed in LCA. [Several refs. provided]

The authors studied a heterozygous CNS-specific Mpp5 KO mouse model. These mice presented microcephaly, decreased cerebellar volume and cortical thickness, decreased ependymal cells and Mpp5 at the apical surface of cortical vertrical zone. The proportion of cortical cells undergoing apoptotic cell death was increased. Mice displayed behavioral abnormalities (hyperactivity) and visual deficits, with ERG traces further suggesting retinal blindness.

Overall the mouse model was thought to recapitulate the behavioral abnormalities observed in affected subjects as well as individual rare features such as microcephaly and abnormal vision.

Haploinsufficiency (rather than a dominant negative effect) is favored as the underlying disease mechanism. This is also in line with a dose dependent effect observed in mice.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3126 ODC1 Zornitza Stark Phenotypes for gene: ODC1 were changed from Intellectual disability; macrocephaly; dysmorphism to Neurodevelopmental disorder with alopecia and brain imaging abnormalities (NEDABIA), MIM#619075
Intellectual disability syndromic and non-syndromic v0.3098 DPH1 Zornitza Stark edited their review of gene: DPH1: Added comment: Four unrelated families reported, 11 affected individuals. Common clinical features include abnormal skull shape (trigonocephaly, scaphocephaly, or prominent forehead accompanied with metopic ridge), distinctive face (downslanted palpebral fissures, low set ears, depressed nasal bridge, and sparse hair on the scalp, eyelashes, and/or eyebrows), short stature, developmental delay, and intellectual disability. Heart and brain malformations are also frequently observed.; Changed publications: 29362492, 29410513, 25558065, 26220823
Intellectual disability syndromic and non-syndromic v0.3081 HECW2 Zornitza Stark reviewed gene: HECW2: Rating: GREEN; Mode of pathogenicity: Other; Publications: 29807643, 29395664, 27334371, 27389779; Phenotypes: Neurodevelopmental disorder with hypotonia, seizures, and absent language, MIM# 617268, intellectual disability, epilepsy, regression, microcephaly; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.3078 CSNK1G1 Konstantinos Varvagiannis changed review comment from: Gold et al (2020 - PMID: 33009664) report 5 individuals with CSNK1G1 variants, including updated information on a previously reported subject (Martin et al 2014 - PMID: 24463883).

Features included DD (5/5) with associated expressive language delay, ASD (in at least 3/5), seizures (2/5), dysmorphic facial features (4/5 arched eyebrows, 3/5 prominent central incisors, 2/5 epicanthus) and limb anomalies (2/5 - proximally placed thumb, 5th f. clinodactyly, asymmetric overgrowth - the other individual had tapering fingers). GI problems were observed in 4/5. Two individuals had macrocephaly and one had microcephaly. There was no formal developmental assessment although ID might be implied in at least 3 individuals (p1: 20y - single words/regression in walking following a seizure episode, p2: 8y - first words at 5y, assistance to feed, dress and bathe, ASD, p4: 13y - regression, assistance to feed and dress).

CSNK1G1 encodes the gamma-1 isoform of casein kinase 1, a protein involved in growth and cell morphogenesis. The gene has ubiquitous expression, incl. brain. As commented, in brain it regulates phosphorylation of NMDA receptors, playing a role in synaptic transmission (4 articles cited).

One individual had a 1.2 kb deletion spanning exon 3 of CSNK1G1 [chr15:64550952-64552120 - GRCh37]. Parental samples were unavailable for this individual. Four individuals were found to harbor de novo CSNK1G1 variants [NM_022048.3: c.688C>T - p.(Arg230Trp) dn | c.1255C>T - p.(Gln419*) dn | c.1214+5G>A dn with in silico predictions in favor of splice disruption | c.419C>T - p.(Thr140Met) dn].

Arg230Trp is however present once in gnomAD. The stopgain variant is located in the last exon and predicted to skip NMD.

There were no variant studies performed.

The Drosophila gish gene encodes a CK1γ homolog with preferential expression in the mushroom body. Heterozygous and homozygous mutants exhibit impairment in memory retention, more severe in homozygous flies. gish was also identified as a seizure modifier in a fly epilepsy model (heterozygous para mt flies).

The authors also speculate that impaired transduction of LRP6 (and WNT signaling) might be implicated.

Finally the authors discuss the phenotype of individuals in Decipher one of whom (327861) harbors a frameshift variant and presenting ID, epilepsy and progressive spasticity. [NB. Inheritance of this variant is not specified, while this individual has a further inherited SCN2A missense SNV]. Two further Decipher cases with microdeletions spanning CSNK1G1 (and additional variants) are also discussed.

Overall, this gene can be considered for inclusion with probably amber rating.
Sources: Literature; to: Gold et al (2020 - PMID: 33009664) report 5 individuals with CSNK1G1 variants, including updated information on a previously reported subject (Martin et al 2014 - PMID: 24463883).

Features included DD (5/5) with associated expressive language delay, ASD (in at least 3/5), seizures (2/5), dysmorphic facial features (4/5 arched eyebrows, 3/5 prominent central incisors, 2/5 epicanthus) and limb anomalies (2/5 - proximally placed thumb, 5th f. clinodactyly, asymmetric overgrowth - the other individual had tapering fingers). GI problems were observed in 4/5. Two individuals had macrocephaly and one had microcephaly. There was no formal developmental assessment although ID might be implied in at least 3 individuals (p1: 20y - single words/regression in walking following a seizure episode, p2: 8y - first words at 5y, assistance to feed, dress and bathe, ASD, p4: 13y - regression, assistance to feed and dress).

CSNK1G1 encodes the gamma-1 isoform of casein kinase 1, a protein involved in growth and cell morphogenesis. The gene has ubiquitous expression, incl. brain. As commented, in brain it regulates phosphorylation of NMDA receptors, playing a role in synaptic transmission (4 articles cited).

One individual had a 1.2 kb deletion spanning exon 3 of CSNK1G1 [chr15:64550952-64552120 - GRCh37]. Parental samples were unavailable for this individual. Four individuals were found to harbor de novo CSNK1G1 variants [NM_022048.3: c.688C>T - p.(Arg230Trp) dn | c.1255C>T - p.(Gln419*) dn | c.1214+5G>A dn with in silico predictions in favor of splice disruption | c.419C>T - p.(Thr140Met) dn].

Arg230Trp is however present once in gnomAD. The stopgain variant is located in the last exon and predicted to skip NMD.

There were no variant studies performed.

The Drosophila gish gene encodes a CK1γ homolog with preferential expression in the mushroom body. Heterozygous and homozygous mutants exhibit impairment in memory retention, more severe in homozygous flies. gish was also identified as a seizure modifier in a fly epilepsy model (heterozygous para mt flies).

The authors also speculate that impaired transduction of LRP6 (and WNT signaling) might be implicated.

Finally the authors discuss the phenotype of individuals in Decipher one of whom (327861) harbors a frameshift variant and presented ID, epilepsy and progressive spasticity. [NB. Inheritance of this variant is not specified, while this individual has a further inherited SCN2A missense SNV]. Two further Decipher cases with microdeletions spanning CSNK1G1 (and additional variants) are also discussed.

Overall, this gene can be considered for inclusion with probably amber rating.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3078 CSNK1G1 Konstantinos Varvagiannis changed review comment from: Gold et al (2020 - PMID: 33009664) report 5 individuals with CSNK1G1 variants, including updated information on a previously reported subject (Martin et al 2014 - PMID: 24463883).

Features included DD (5/5) with associated expressive language delay, ASD (in at least 3/5), seizures (2/5), dysmorphic facial features (4/5 arched eyebrows, 3/5 prominent central incisors, 2/5 epicanthus) and limb anomalies (2/5 - proximally placed thumb, 5th f. clinodactyly, asymmetric overgrowth - the other individual had tapering fingers). GI problems were observed in 4/5. Two individuals had macrocephaly and one had microcephaly. There was no formal developmental assessment although ID might be implied in at least 3 individuals (p1: 20y - single words/regression in walking following a seizure episode, p2: 8y - first words at 5y, assistance to feed, dress and bathe, ASD, p4: 13y - regression, assistance to feed and dress).

CSNK1G1 encodes the gamma-1 isoform of casein kinase 1, a protein involved in growth and cell morphogenesis. The gene has ubiquitous expression, incl. brain. As commented, in brain it regulates phosphorylation of NMDA receptors, playing a role in synaptic transmission (4 articles cited).

One individual had a 1.2 kb deletion spanning exon 3 of CSNK1G1 [chr15:64550952-64552120 - GRCh37]. Parental samples were unavailable for this individual. Four individuals were found to harbor de novo CSNK1G1 variants [NM_022048.3: c.688C>T - p.(Arg230Trp) dn | c.1255C>T - p.(Gln419*) dn | c.1214+5G>A dn with in silico predictions in favor of splice disruption | c.419C>T - p.(Thr140Met) dn].

Arg230Trp is however present once in gnomAD. The stopgain variant is located in the last exon and predicted to skip NMD.

There were no variant studies performed.

The Drosophila gish gene encodes a CK1γ homolog with preferential expression in the mushroom body. Heterozygous and homozygous mutants exhibit impairment in memory retention, more severe in homozygous flies. gish was also identified as a seizure modifier in a fly epilepsy model (heterozygous para mt flies).

The authors also speculate that impaired transduction of LRP6 (and WNT signaling) might be implicated.

Finally the authors discuss the phenotype of individuals in Decipher one of whom (327861) harbors a frameshift variant and presenting ID, epilepsy and progressive spasticity. [NB. Inheritance of this variant is not specified, while this individual has a further inherited SCN2A missense SNV]. Two further Decipher cases with microdeletions spanning CSNK1G1 (and additional variants) also discussed.

Overall, this gene can be considered for inclusion with probably amber rating.
Sources: Literature; to: Gold et al (2020 - PMID: 33009664) report 5 individuals with CSNK1G1 variants, including updated information on a previously reported subject (Martin et al 2014 - PMID: 24463883).

Features included DD (5/5) with associated expressive language delay, ASD (in at least 3/5), seizures (2/5), dysmorphic facial features (4/5 arched eyebrows, 3/5 prominent central incisors, 2/5 epicanthus) and limb anomalies (2/5 - proximally placed thumb, 5th f. clinodactyly, asymmetric overgrowth - the other individual had tapering fingers). GI problems were observed in 4/5. Two individuals had macrocephaly and one had microcephaly. There was no formal developmental assessment although ID might be implied in at least 3 individuals (p1: 20y - single words/regression in walking following a seizure episode, p2: 8y - first words at 5y, assistance to feed, dress and bathe, ASD, p4: 13y - regression, assistance to feed and dress).

CSNK1G1 encodes the gamma-1 isoform of casein kinase 1, a protein involved in growth and cell morphogenesis. The gene has ubiquitous expression, incl. brain. As commented, in brain it regulates phosphorylation of NMDA receptors, playing a role in synaptic transmission (4 articles cited).

One individual had a 1.2 kb deletion spanning exon 3 of CSNK1G1 [chr15:64550952-64552120 - GRCh37]. Parental samples were unavailable for this individual. Four individuals were found to harbor de novo CSNK1G1 variants [NM_022048.3: c.688C>T - p.(Arg230Trp) dn | c.1255C>T - p.(Gln419*) dn | c.1214+5G>A dn with in silico predictions in favor of splice disruption | c.419C>T - p.(Thr140Met) dn].

Arg230Trp is however present once in gnomAD. The stopgain variant is located in the last exon and predicted to skip NMD.

There were no variant studies performed.

The Drosophila gish gene encodes a CK1γ homolog with preferential expression in the mushroom body. Heterozygous and homozygous mutants exhibit impairment in memory retention, more severe in homozygous flies. gish was also identified as a seizure modifier in a fly epilepsy model (heterozygous para mt flies).

The authors also speculate that impaired transduction of LRP6 (and WNT signaling) might be implicated.

Finally the authors discuss the phenotype of individuals in Decipher one of whom (327861) harbors a frameshift variant and presenting ID, epilepsy and progressive spasticity. [NB. Inheritance of this variant is not specified, while this individual has a further inherited SCN2A missense SNV]. Two further Decipher cases with microdeletions spanning CSNK1G1 (and additional variants) are also discussed.

Overall, this gene can be considered for inclusion with probably amber rating.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3078 CSNK1G1 Konstantinos Varvagiannis gene: CSNK1G1 was added
gene: CSNK1G1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CSNK1G1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: CSNK1G1 were set to 33009664
Phenotypes for gene: CSNK1G1 were set to Global developmental delay; Intellectual disability; Autism; Seizures; Abnormality of the face; Abnromality of limbs
Penetrance for gene: CSNK1G1 were set to unknown
Review for gene: CSNK1G1 was set to AMBER
Added comment: Gold et al (2020 - PMID: 33009664) report 5 individuals with CSNK1G1 variants, including updated information on a previously reported subject (Martin et al 2014 - PMID: 24463883).

Features included DD (5/5) with associated expressive language delay, ASD (in at least 3/5), seizures (2/5), dysmorphic facial features (4/5 arched eyebrows, 3/5 prominent central incisors, 2/5 epicanthus) and limb anomalies (2/5 - proximally placed thumb, 5th f. clinodactyly, asymmetric overgrowth - the other individual had tapering fingers). GI problems were observed in 4/5. Two individuals had macrocephaly and one had microcephaly. There was no formal developmental assessment although ID might be implied in at least 3 individuals (p1: 20y - single words/regression in walking following a seizure episode, p2: 8y - first words at 5y, assistance to feed, dress and bathe, ASD, p4: 13y - regression, assistance to feed and dress).

CSNK1G1 encodes the gamma-1 isoform of casein kinase 1, a protein involved in growth and cell morphogenesis. The gene has ubiquitous expression, incl. brain. As commented, in brain it regulates phosphorylation of NMDA receptors, playing a role in synaptic transmission (4 articles cited).

One individual had a 1.2 kb deletion spanning exon 3 of CSNK1G1 [chr15:64550952-64552120 - GRCh37]. Parental samples were unavailable for this individual. Four individuals were found to harbor de novo CSNK1G1 variants [NM_022048.3: c.688C>T - p.(Arg230Trp) dn | c.1255C>T - p.(Gln419*) dn | c.1214+5G>A dn with in silico predictions in favor of splice disruption | c.419C>T - p.(Thr140Met) dn].

Arg230Trp is however present once in gnomAD. The stopgain variant is located in the last exon and predicted to skip NMD.

There were no variant studies performed.

The Drosophila gish gene encodes a CK1γ homolog with preferential expression in the mushroom body. Heterozygous and homozygous mutants exhibit impairment in memory retention, more severe in homozygous flies. gish was also identified as a seizure modifier in a fly epilepsy model (heterozygous para mt flies).

The authors also speculate that impaired transduction of LRP6 (and WNT signaling) might be implicated.

Finally the authors discuss the phenotype of individuals in Decipher one of whom (327861) harbors a frameshift variant and presenting ID, epilepsy and progressive spasticity. [NB. Inheritance of this variant is not specified, while this individual has a further inherited SCN2A missense SNV]. Two further Decipher cases with microdeletions spanning CSNK1G1 (and additional variants) also discussed.

Overall, this gene can be considered for inclusion with probably amber rating.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3078 LMNB2 Konstantinos Varvagiannis changed review comment from: Please consider inclusion of LMNB2 in the ID panel with amber/green rating.

Parry et al (2020 - PMID: 33033404) in a study to identify novel microcephaly genes using the DDD and 100k genomes project (100kGP) patient cohort, report on the phenotype of 13 individuals with heterozygous variant in LMNB1 (N=7) and LMNB2 (N=6).

LMNB1 : The authors identified 3 recurrent variants (c.97A>G - p.Lys33Glu (3), c.97_99del - p.Lys33del (2) , c.269G>C - p.Arg90Pro (2) / NM_005573.4) in seven individuals (3 from the DDD study, 4 from the 100kGP). In all cases were segregation studies were possible, the variant had occurred as a de novo event.

LMNB2 : 4 individuals from the DDD cohort and 1 from the 100kGP were found to harbor the same missense SNV (NM_032737.4:c.1192G>A, p.Glu398Lys). The variant had occurred de novo in 3 subjects and was inherited from a mosaic - unaffected - parent in a further case. Another individual was found to harbor c.160A>C - p.Asn54His.

LMNB1/2 common phenotypes :
All cases had congenital microcephaly (OFC -5.85 +/- 1.14 SD) appart from one individual, without history of IUGR or postnatally abnormal height (the latter in most).

Neuroimaging suggested structurally normal brain without abnormal migration. Gyral simplification / global reduction in white matter / increased extra axial spaces / enlarged ventricles were reported in 2.

LMNB1 - Global developmental delay was a feature in all (mild to severe) with some having occasional words at 7y (P3), absent speech (P9 - age category 5-10y) or ID not further specified (P13).

LMNB2 - DD was a feature in all 6 subjects (5/6 moderate to severe - 1/6 GDD). 5/6 were 10y or older with language (in 3 language not achieved) and motor deficits (walking not achieved in 1/6 - occured at the age of 6y in 1/6).

Facial features were not consistent nor suggestive of a syndromic diagnosis (sloping forehead in some).

Overall, as the authors comment, the phenotype corresponded to a severe nonsyndromic microcephaly (although additional features were reported in some).

Animal model:
Microcephaly is supported by Lmnb1 ko mouse model. Lmnb1/2 ko mice however display migration defects, while Lmnb2 ko mice do not have reduced size at birth. Heterozygous Lmnb1 mice do not present microcephaly. It is suggested that while animal models support a similar (to the human) phenotype the underlying mechanism is different.

Variant effect :
variants were shown to affect highly conserved residues within the lamin a-helical rod-domain. As affected residues are conserved in LMNA, modelling with available LMNA PDB structures, suggested disrupted interactions required for higher-order assembly of lamin filaments.

Recurrence of specific variants at specific residues, absence of pLoF ones, the htz mouse Lmnb1 phenotype (absence of microcephaly) and the proposed mechanism (perturbation of complex formation) suggest a gain-of-function/dominant-negative effect rather than happloinsufficiency.

[Please also note the additional OMIM phenotypes for LMNB1 / LMNB2 - not here reviewed]
Sources: Literature; to: Please consider inclusion of LMNB2 in the ID panel with amber/green rating.

Parry et al (2020 - PMID: 33033404) in a study to identify novel microcephaly genes using the DDD and 100k genomes project (100kGP) patient cohort, report on the phenotype of 13 individuals with heterozygous variant in LMNB1 (N=7) and LMNB2 (N=6).

LMNB1 : The authors identified 3 recurrent variants (c.97A>G - p.Lys33Glu (3), c.97_99del - p.Lys33del (2) , c.269G>C - p.Arg90Pro (2) / NM_005573.4) in seven individuals (3 from the DDD study, 4 from the 100kGP). In all cases were segregation studies were possible, the variant had occurred as a de novo event.

LMNB2 : 4 individuals from the DDD cohort and 1 from the 100kGP were found to harbor the same missense SNV (NM_032737.4:c.1192G>A, p.Glu398Lys). The variant had occurred de novo in 3 subjects and was inherited from a mosaic - unaffected - parent in a further case. Another individual was found to harbor c.160A>C - p.Asn54His.

LMNB1/2 common phenotypes :
All cases had congenital microcephaly (OFC -5.85 +/- 1.14 SD) apart from one individual, without history of IUGR or postnatally abnormal height (the latter in most).

Neuroimaging suggested structurally normal brain without abnormal migration. Gyral simplification / global reduction in white matter / increased extra axial spaces / enlarged ventricles were reported in 2.

LMNB1 - Global developmental delay was a feature in all (mild to severe) with some having occasional words at 7y (P3), absent speech (P9 - age category 5-10y) or ID not further specified (P13).

LMNB2 - DD was a feature in all 6 subjects (5/6 moderate to severe - 1/6 GDD). 5/6 were 10y or older with language (in 3 language not achieved) and motor deficits (walking not achieved in 1/6 - occurred at the age of 6y in 1/6).

Facial features were not consistent nor suggestive of a syndromic diagnosis (sloping forehead in some).

Overall, as the authors comment, the phenotype corresponded to a severe nonsyndromic microcephaly (although additional features were reported in some).

Animal model:
Microcephaly is supported by Lmnb1 ko mouse model. Lmnb1/2 ko mice however display migration defects, while Lmnb2 ko mice do not have reduced size at birth. Heterozygous Lmnb1 mice do not present microcephaly. It is suggested that while animal models support a similar (to the human) phenotype the underlying mechanism is different.

Variant effect :
variants were shown to affect highly conserved residues within the lamin a-helical rod-domain. As affected residues are conserved in LMNA, modelling with available LMNA PDB structures, suggested disrupted interactions required for higher-order assembly of lamin filaments.

Recurrence of specific variants at specific residues, absence of pLoF ones, the htz mouse Lmnb1 phenotype (absence of microcephaly) and the proposed mechanism (perturbation of complex formation) suggest a gain-of-function/dominant-negative effect rather than happloinsufficiency.

[Please also note the additional OMIM phenotypes for LMNB1 / LMNB2 - not here reviewed]
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3078 LMNB2 Konstantinos Varvagiannis gene: LMNB2 was added
gene: LMNB2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: LMNB2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: LMNB2 were set to 33033404
Phenotypes for gene: LMNB2 were set to Congenital microcephaly; Global developmental delay; Intellectual disability
Penetrance for gene: LMNB2 were set to Complete
Mode of pathogenicity for gene: LMNB2 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: LMNB2 was set to GREEN
Added comment: Please consider inclusion of LMNB2 in the ID panel with amber/green rating.

Parry et al (2020 - PMID: 33033404) in a study to identify novel microcephaly genes using the DDD and 100k genomes project (100kGP) patient cohort, report on the phenotype of 13 individuals with heterozygous variant in LMNB1 (N=7) and LMNB2 (N=6).

LMNB1 : The authors identified 3 recurrent variants (c.97A>G - p.Lys33Glu (3), c.97_99del - p.Lys33del (2) , c.269G>C - p.Arg90Pro (2) / NM_005573.4) in seven individuals (3 from the DDD study, 4 from the 100kGP). In all cases were segregation studies were possible, the variant had occurred as a de novo event.

LMNB2 : 4 individuals from the DDD cohort and 1 from the 100kGP were found to harbor the same missense SNV (NM_032737.4:c.1192G>A, p.Glu398Lys). The variant had occurred de novo in 3 subjects and was inherited from a mosaic - unaffected - parent in a further case. Another individual was found to harbor c.160A>C - p.Asn54His.

LMNB1/2 common phenotypes :
All cases had congenital microcephaly (OFC -5.85 +/- 1.14 SD) appart from one individual, without history of IUGR or postnatally abnormal height (the latter in most).

Neuroimaging suggested structurally normal brain without abnormal migration. Gyral simplification / global reduction in white matter / increased extra axial spaces / enlarged ventricles were reported in 2.

LMNB1 - Global developmental delay was a feature in all (mild to severe) with some having occasional words at 7y (P3), absent speech (P9 - age category 5-10y) or ID not further specified (P13).

LMNB2 - DD was a feature in all 6 subjects (5/6 moderate to severe - 1/6 GDD). 5/6 were 10y or older with language (in 3 language not achieved) and motor deficits (walking not achieved in 1/6 - occured at the age of 6y in 1/6).

Facial features were not consistent nor suggestive of a syndromic diagnosis (sloping forehead in some).

Overall, as the authors comment, the phenotype corresponded to a severe nonsyndromic microcephaly (although additional features were reported in some).

Animal model:
Microcephaly is supported by Lmnb1 ko mouse model. Lmnb1/2 ko mice however display migration defects, while Lmnb2 ko mice do not have reduced size at birth. Heterozygous Lmnb1 mice do not present microcephaly. It is suggested that while animal models support a similar (to the human) phenotype the underlying mechanism is different.

Variant effect :
variants were shown to affect highly conserved residues within the lamin a-helical rod-domain. As affected residues are conserved in LMNA, modelling with available LMNA PDB structures, suggested disrupted interactions required for higher-order assembly of lamin filaments.

Recurrence of specific variants at specific residues, absence of pLoF ones, the htz mouse Lmnb1 phenotype (absence of microcephaly) and the proposed mechanism (perturbation of complex formation) suggest a gain-of-function/dominant-negative effect rather than happloinsufficiency.

[Please also note the additional OMIM phenotypes for LMNB1 / LMNB2 - not here reviewed]
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3078 LMNB1 Konstantinos Varvagiannis commented on gene: LMNB1: There is an additional report on LMBN1/2-associated phenotypes supporting green rating of the gene in the current panel.

Parry et al (2020 - PMID: 33033404) in a study to identify novel microcephaly genes using the DDD and 100k genomes project (100kGP) patient cohort, report on the phenotype of 13 individuals with heterozygous variant in LMNB1 (N=7) and LMNB2 (N=6).

LMNB1 : The authors identified 3 recurrent variants (c.97A>G - p.Lys33Glu (3), c.97_99del - p.Lys33del (2) , c.269G>C - p.Arg90Pro (2) / NM_005573.4) in seven individuals (3 from the DDD study, 4 from the 100kGP). In all cases were segregation studies were possible, the variant had occurred as a de novo event.

LMNB2 : 4 individuals from the DDD cohort and 1 from the 100kGP were found to harbor the same missense SNV (NM_032737.4:c.1192G>A, p.Glu398Lys). The variant had occurred de novo in 3 subjects and was inherited from a mosaic - unaffected - parent in a further case. Another individual was found to harbor c.160A>C - p.Asn54His.

LMNB1/2 common phenotypes :
All cases had congenital microcephaly (OFC -5.85 +/- 1.14 SD) appart from one individual, without history of IUGR or postnatally abnormal height (the latter in most).

Neuroimaging suggested structurally normal brain without abnormal migration. Gyral simplification / global reduction in white matter / increased extra axial spaces / enlarged ventricles were reported in 2.

LMNB1 - Global developmental delay was a feature in all (mild to severe) with some having occasional words at 7y (P3), absent speech (P9 - age category 5-10y) or ID not further specified (P13).

LMNB2 - DD was a feature in all 6 subjects (5/6 moderate to severe - 1/6 GDD). 5/6 were 10y or older with language (in 3 language not achieved) and motor deficits (walking not achieved in 1/6 - occured at the age of 6y in 1/6).

Facial features were not consistent nor suggestive of a syndromic diagnosis (sloping forehead in some).

Overall, as the authors comment, the phenotype corresponded to a severe nonsyndromic microcephaly (although additional features were reported in some).

Animal model:
Microcephaly is supported by Lmnb1 ko mouse model. Lmnb1/2 ko mice however display migration defects, while Lmnb2 ko mice do not have reduced size at birth. Heterozygous Lmnb1 mice do not present microcephaly. It is suggested that while animal models support a similar (to the human) phenotype the underlying mechanism is different.

Variant effect :
variants were shown to affect highly conserved residues within the lamin a-helical rod-domain. As affected residues are conserved in LMNA, modelling with available LMNA PDB structures, suggested disrupted interactions required for higher-order assembly of lamin filaments.

Recurrence of specific variants at specific residues, absence of pLoF ones, the htz mouse Lmnb1 phenotype (absence of microcephaly) and the proposed mechanism (perturbation of complex formation) suggest a gain-of-function/dominant-negative effect rather than happloinsufficiency.

[Please also note the additional OMIM phenotypes for LMNB1 / LMNB2 - not here reviewed]

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Intellectual disability syndromic and non-syndromic v0.3062 SHMT2 Konstantinos Varvagiannis gene: SHMT2 was added
gene: SHMT2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SHMT2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SHMT2 were set to 33015733
Phenotypes for gene: SHMT2 were set to Congenital microcephaly; Infantile axial hypotonia; Spastic paraparesis; Global developmental delay; Intellectual disability; Abnormality of the corpus callosum; Abnormal cortical gyration; Hypertrophic cardiomyopathy; Abnormality of the face; Proximal placement of thumb; 2-3 toe syndactyly
Penetrance for gene: SHMT2 were set to Complete
Review for gene: SHMT2 was set to GREEN
Added comment: García‑Cazorla et al. (2020 - PMID: 33015733) report 5 individuals (from 4 families) with a novel brain and heart developmental syndrome caused by biallelic SHMT2 pathogenic variants.

All affected subjects presented similar phenotype incl. microcephaly at birth (5/5 with OFC < -2 SD though in 2/5 cases N OFC was observed later), DD and ID (1/5 mild-moderate, 1/5 moderate, 3/5 severe), motor dysfunction in the form of spastic (5/5) paraparesis, ataxia/dysmetria (3/4), intention tremor (in 3/?) and/or peripheral neuropathy (2 sibs). They exhibited corpus callosum hypoplasia (5/5) and perisylvian microgyria-like pattern (4/5). Cardiac problems were reported in all, with hypertrophic cardiomyopathy in 4/5 (from 3 families) and atrial-SD in the 5th individual (1/5). Common dysmorphic features incl. long palpebral/fissures, eversion of lateral third of lower eylids, arched eyebrows, long eyelashes, thin upper lip, short Vth finger, fetal pads, mild 2-3 toe syndactyly, proximally placed thumbs.

Biallelic variants were identified following exome sequencing in all (other investigations not mentioned). Identified variants were in all cases missense SNVs or in-frame del, which together with evidence from population databases and mouse model might suggest a hypomorphic effect of variants and intolerance/embryonic lethality for homozygous LoF ones.

SHMT2 encodes the mitohondrial form of serine hydroxymethyltransferase. The enzyme transfers one-carbon units from serine to tetrahydrofolate (THF) and generates glycine and 5,10,methylene-THF.

Mitochondrial defect was suggested by presence of ragged red fibers in myocardial biopsy of one patient. Quadriceps and myocardial biopsies of the same individual were overall suggestive of myopathic changes.

While plasma metabolites were within N range and SHMT2 protein levels not significantly altered in patient fibroblasts, the authors provide evidence for impaired enzymatic function eg. presence of the SHMT2 substrate (THF) in patient but not control (mitochondria-enriched) fibroblasts , decrease in glycine/serine ratios, impared folate metabolism. Patient fibroblasts displayed impaired oxidative capacity (reduced ATP levels in a medium without glucose, diminished oxygen consumption rates). Mitochondrial membrane potential and ROS levels were also suggestive of redox malfunction.

Shmt2 ko in mice was previously shown to be embryonically lethal attributed to severe mitochondrial respiration defects, although there was no observed brain metabolic defect.

The authors performed Shmt2 knockdown in motoneurons in Drosophila, demonstrating neuromuscular junction (# of satellite boutons) and motility defects (climbing distance/velocity).

Overall this gene can be considered for inclusion with (probably) green rating in gene panels for ID, metabolic / mitochondrial disorders, cardiomyopathy, congenital microcephaly, corpus callosum anomalies, etc.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3053 NUP188 Zornitza Stark Phenotypes for gene: NUP188 were changed from microcephaly; ID; cataract; structural brain abnormalities; hypoventilation to Sandestig-Stefanova syndrome, 618804; microcephaly; ID; cataract; structural brain abnormalities; hypoventilation
Intellectual disability syndromic and non-syndromic v0.3052 NUP188 Zornitza Stark edited their review of gene: NUP188: Changed phenotypes: Sandestig-Stefanova syndrome, 618804, microcephaly, ID, cataract, structural brain abnormalities, hypoventilation
Intellectual disability syndromic and non-syndromic v0.3050 HPDL Zornitza Stark changed review comment from: Intellectual impairment is variable, ranging from poor visual contact with inability to walk or speak to milder intellectual disability with the ability to say some words.; to: 17 individuals from 13 families, with a spectrum of neurologic impairment ranging from a severe congenital form without any neurological development (n = 2/17, 12%) to infantile-onset presentations (n = 10/17, 59%) with moderate to severe neurodevelopmental issues, partly with a pathology reminiscent of mitochondrial disease (Leigh-like syndrome), to juvenile-onset spastic paraplegia (n = 5/17, 29%).

Intellectual impairment is variable, ranging from poor visual contact with inability to walk or speak to milder intellectual disability with the ability to say some words.

Frequently observed additional clinical findings included chronic progression of neurological signs (n = 16/17, 94%), microcephaly (n = 9/16, 56%), and seizures/epilepsy (n = 9/17, 53%). Other relevant clinical findings were visual disturbances/strabismus (n = 9/17, 53%) and loss of developmental milestones (n = 6/17, 35%).

Acute central respiratory failure leading to life-threatening events requiring partly mechanically assisted ventilation occurred in half of individuals with infantile presentation (n = 5/10, 50%), respectively one third of all individuals (n = 5/17, 29%).

Demyelinating neuropathy was present in three individuals (n = 3/11, 27%), with reduced sensory nerve conduction velocity (NCV) in all and severely reduced motor NCV in one.
Intellectual disability syndromic and non-syndromic v0.3030 CNOT1 Zornitza Stark Phenotypes for gene: CNOT1 were changed from Holoprosencephaly 12, with or without pancreatic agenesis 618500 to Vissers-Bodmer syndrome, MIM#619033; Holoprosencephaly 12, with or without pancreatic agenesis 618500
Intellectual disability syndromic and non-syndromic v0.3028 COQ5 Zornitza Stark Phenotypes for gene: COQ5 were changed from Cerebellar ataxia; encephalopathy; generalized tonic-clonic seizures; intellectual disability to Coenzyme Q10 deficiency, primary 9, MIM#619028; Cerebellar ataxia; encephalopathy; generalized tonic-clonic seizures; intellectual disability
Intellectual disability syndromic and non-syndromic v0.3027 COQ5 Zornitza Stark edited their review of gene: COQ5: Changed phenotypes: Coenzyme Q10 deficiency, primary 9, MIM#619028, Cerebellar ataxia, encephalopathy, generalized tonic-clonic seizures, intellectual disability
Intellectual disability syndromic and non-syndromic v0.3013 ZMYM2 Konstantinos Varvagiannis gene: ZMYM2 was added
gene: ZMYM2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZMYM2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: ZMYM2 were set to 32891193
Phenotypes for gene: ZMYM2 were set to Abnormality of the urinary system; Global developmental delay; Intellectual disability; Microcephaly; Abnormality of the cardiovascular system; Autism; Seizures; Abnormality of the head or neck; Abnormality of the nail; Small hand; Short foot; Clinodactyly
Penetrance for gene: ZMYM2 were set to unknown
Review for gene: ZMYM2 was set to AMBER
Added comment: Heterozygous pathogenic (pLoF) ZMYM2 variants have been reported in individuals with syndromic presentation including CAKUT (in several cases) and variable neurological manifestations among extra-renal features. DD and ID were reported in some of the families described to date as summarized below. You might consider inclusion with green/amber rating in the ID panel and green in the panel for CAKUT.

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Connaughton et al (2020 - PMID: 32891193) report on 19 individuals (from 15 unrelated families) with heterozygous pathogenic ZMYM2 variants. [Article not reviewed in detail].

Affected individuals from 7 families presented with CAKUT while all of them displayed extra-renal features. Neurological manifestations were reported in 16 individuals from 14 families (data not available for 1 fam), among others hypotonia (3/14 fam), speech delay (4/14 fam), global DD (9/14 fam), ID (4/14 fam), microcephaly (4/14 fam). ASD was reported in 4 fam (4 indiv). Seizures were reported in 2 fam (2 indiv). Variable other features included cardiac defects, facial dysmorphisms, small hands and feet with dys-/hypo-plastic nails and clinodactyly.

14 pLoF variants were identified, in most cases as de novo events (8 fam). In 2 families the variant was inherited from an affected parent. Germline mosaicism occurred in 1 family.

The human disease features were recapitulated in a X. tropicalis morpholino knockdown, with expression of truncating variants failing to rescue renal and craniofacial defects. Heterozygous Zmym2-deficient mice also recapitulated the features of CAKUT.

ZMYM2 (previously ZNF198) encodes a nuclear zinc finger protein localizing to the nucleus (and PML nuclear body).

It has previously been identified as transcriptional corepressor interacting with nuclear receptors and the LSD1-CoREST-HDAC1 complex. It has also been shown to interact with FOXP transcription factors.

The authors provide evidence for loss of interaction of the truncated ZMYM2 with FOXP1 (mutations in the latter having recently been reported in syndromic CAKUT).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.3011 LMNB1 Zornitza Stark Phenotypes for gene: LMNB1 were changed from Leukodystrophy, adult-onset, autosomal dominant, MIM#169500 to Global developmental delay, Intellectual disability, Microcephaly, Short stature, Seizures, Abnormality of the corpus callosum, Cortical gyral simplification, Feeding difficulties, Scoliosis; Leukodystrophy, adult-onset, autosomal dominant, MIM#169500
Intellectual disability syndromic and non-syndromic v0.3007 LMNB1 Konstantinos Varvagiannis reviewed gene: LMNB1: Rating: GREEN; Mode of pathogenicity: Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments; Publications: 32910914; Phenotypes: Global developmental delay, Intellectual disability, Microcephaly, Short stature, Seizures, Abnormality of the corpus callosum, Cortical gyral simplification, Feeding difficulties, Scoliosis; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability syndromic and non-syndromic v0.3007 SVBP Zornitza Stark reviewed gene: SVBP: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Neurodevelopmental disorder with ataxia, hypotonia, and microcephaly, OMIM #618569; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.3006 KCNA2 Zornitza Stark Phenotypes for gene: KCNA2 were changed from to Early infantile encephalopathy 32, MIM#616366
Intellectual disability syndromic and non-syndromic v0.3003 KCNA2 Zornitza Stark reviewed gene: KCNA2: Rating: GREEN; Mode of pathogenicity: None; Publications: 29050392; Phenotypes: Early infantile encephalopathy 32, MIM#616366; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2954 TRIP13 Zornitza Stark changed review comment from: Early-onset Wilms tumor and either aneuploidy or premature chromatid separation in cells. Some individuals described as having additional developmental features, such as microcephaly, growth retardation, or developmental delay but these are highly variable.; to: Early-onset Wilms tumor and either aneuploidy or premature chromatid separation in cells. Some individuals described as having additional developmental features, such as microcephaly, growth retardation, or developmental delay but these are highly variable. Also note 5/6 reported families had the same homozygous variant, p.Arg354X, suggestive of founder effect.
Intellectual disability syndromic and non-syndromic v0.2954 TRAPPC6B Zornitza Stark Phenotypes for gene: TRAPPC6B were changed from to Neurodevelopmental disorder with microcephaly, epilepsy, and brain atrophy, MIM# 617862
Intellectual disability syndromic and non-syndromic v0.2951 TRAPPC6B Zornitza Stark reviewed gene: TRAPPC6B: Rating: GREEN; Mode of pathogenicity: None; Publications: 28626029, 28397838, 31687267; Phenotypes: Neurodevelopmental disorder with microcephaly, epilepsy, and brain atrophy, MIM# 617862; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2949 DHX37 Naomi Baker gene: DHX37 was added
gene: DHX37 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: DHX37 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: DHX37 were set to PMID: 26539891; 31256877
Phenotypes for gene: DHX37 were set to Neurodevelopmental disorder with brain anomalies and with or without vertebral or cardiac anomalies, MIM#618731
Review for gene: DHX37 was set to GREEN
Added comment: Two unrelated patients from consanguineous families reported with biallelic missense variants. Clinical presentation included severe microcephaly, DD/ID, and cortical atrophy (PMID: 26539891).

Five individuals who share a phenotype of DD and/or ID and CNS dysfunction. Three out of five individuals also have scoliosis, and two have cardiac phenotypes (PMID: 31256877). Three of the patients had bialleleic missense variants, while two patients had a de novo monoallelic missense variant.

Note that OMIM lists inheritance as biallelic, however two monoallelic cases reportes.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2943 PLK4 Zornitza Stark Phenotypes for gene: PLK4 were changed from to Microcephaly and chorioretinopathy, autosomal recessive, 2, MIM# 616171
Intellectual disability syndromic and non-syndromic v0.2940 PLK4 Zornitza Stark reviewed gene: PLK4: Rating: GREEN; Mode of pathogenicity: None; Publications: 25344692, 25320347, 27650967; Phenotypes: Microcephaly and chorioretinopathy, autosomal recessive, 2, MIM# 616171; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2939 TRAPPC2L Zornitza Stark gene: TRAPPC2L was added
gene: TRAPPC2L was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TRAPPC2L was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TRAPPC2L were set to 30120216; 32843486
Phenotypes for gene: TRAPPC2L were set to Encephalopathy, progressive, early-onset, with episodic rhabdomyolysis, 618331
Review for gene: TRAPPC2L was set to AMBER
Added comment: Total of three families, but two share a founder variant, and there are some disparities between the clinical presentations reported in the two publications. Rating Amber as additional cases required to delineate the genotype-phenotype relationship. PMID: 30120216 (2018) - Two unrelated probands with an identical homozygous missense (c.109G>T, p.Asp37Tyr) variant in TRAPPC2L. Both individuals presented neurodevelopmental delay, febrile illness-induced encephalopathy, and episodic rhabdomyolysis, followed by developmental arrest, seizures and tetraplegia. The variant segregated with the phenotype in each family, and haplotype analysis suggested a founder effect. The mutant protein was expressed in patient fibroblasts, but displayed membrane trafficking delays. Studies in yeast showed that the variant impaired interaction with TRAPPC10, and increased levels of the active RAB11. PMID: 32843486 (2020) - In an Ashkenazi Jewish family with three affected sibs with GDD/ID, WGS revealed a segregating homozygous missense variant (c.5G>C, p.Ala2Gly) in the TRAPPC2L gene. No seizures, brain MRI abnormalities, or illness provoked regression were documented in this family. Comparable to the previous study, the variant resulted in delayed ER-to-Golgi trafficking and elevated levels of active RAB11. Studies using yeast and in vitro binding, showed that the variant disrupted interaction with another core TRAPP protein, TRAPPC6a.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2920 CTNND1 Zornitza Stark gene: CTNND1 was added
gene: CTNND1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CTNND1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CTNND1 were set to 28301459; 32196547
Phenotypes for gene: CTNND1 were set to Blepharocheilodontic syndrome 2, MIM# 617681
Review for gene: CTNND1 was set to AMBER
Added comment: 4 individuals from 3 unrelated families with blepharocheilodontic syndrome and mutations in the CTNND1 gene reported originally in PMID 28301459. All had eyelid anomalies, including ectropion of the lower lids, euryblepharon, lagophthalmia, and distichiasis. In addition, all 4 showed typical facial dysmorphism with hypertelorism, flat face, and high forehead, and all had conical teeth and tooth agenesis. Three had cleft lip and palate, 3 had hair anomalies, and 1 had hypothyroidism due to hypoplasia or aplasia of the thyroid gland. None of the patients exhibited anal atresia or neural tube defects.

PMID: 32196547 - Alharatani et al 2020 - report an expanded phenotype for CTNND1 patients. They report 13 individuals from nine families with novel protein-truncating variants in CTNND1 identified by WES. The mutations were not previously described in blepharocheilodontic (BCD), orofacial cleft cases nor in gnomAD. 8 patients had de novo variants, 2 inherited from affected parents, 2 participants inherited a variant from a parent with a mild phenotype. 8/13 patients showed cleft palate. Additional phenotypic features seen include mild limb phenotypes (9/13), cardiovascular anomalies (6/13) and Developmental delay and other neurodevelopmental problems (8/13).

This more recent publication suggests a broader phenotype associated with CTNND1 variants including dev delay, ADHD/ASD, behavioural issues. Unclear from description whether significant ID present.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2919 ADARB1 Zornitza Stark Phenotypes for gene: ADARB1 were changed from Intellectual disability; microcephaly; seizures to Neurodevelopmental disorder with hypotonia, microcephaly, and seizures, 618862; Intellectual disability; microcephaly; seizures
Intellectual disability syndromic and non-syndromic v0.2917 ADARB1 Arina Puzriakova reviewed gene: ADARB1: Rating: GREEN; Mode of pathogenicity: None; Publications: 32220291, 32719099; Phenotypes: Neurodevelopmental disorder with hypotonia, microcephaly, and seizures, 618862; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2917 KIF14 Zornitza Stark Phenotypes for gene: KIF14 were changed from to Microcephaly 20, primary, autosomal recessive, MIM# 617914; Meckel syndrome 12, MIM# 616258
Intellectual disability syndromic and non-syndromic v0.2914 KIF14 Zornitza Stark reviewed gene: KIF14: Rating: GREEN; Mode of pathogenicity: None; Publications: 28892560, 29343805; Phenotypes: Microcephaly 20, primary, autosomal recessive, MIM# 617914, Meckel syndrome 12, MIM# 616258; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2907 NSD2 Zornitza Stark Phenotypes for gene: NSD2 were changed from to Microcephaly; intellectual disability
Intellectual disability syndromic and non-syndromic v0.2905 NSD2 Zornitza Stark reviewed gene: NSD2: Rating: GREEN; Mode of pathogenicity: None; Publications: 30345613, 31171569; Phenotypes: Microcephaly, intellectual disability; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2897 AARS Zornitza Stark Phenotypes for gene: AARS were changed from to Epileptic encephalopathy, early infantile, 29, MIM# 616339
Intellectual disability syndromic and non-syndromic v0.2894 AARS Zornitza Stark reviewed gene: AARS: Rating: GREEN; Mode of pathogenicity: None; Publications: 28493438, 25817015; Phenotypes: Epileptic encephalopathy, early infantile, 29, MIM# 616339; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2894 PAFAH1B1 Zornitza Stark Phenotypes for gene: PAFAH1B1 were changed from to Lissencephaly 1, MIM# 607432; Subcortical laminar heterotopia, MIM# 607432; MONDO:0011830
Intellectual disability syndromic and non-syndromic v0.2891 PAFAH1B1 Zornitza Stark reviewed gene: PAFAH1B1: Rating: GREEN; Mode of pathogenicity: None; Publications: 11754098, 18285425; Phenotypes: Lissencephaly 1, MIM# 607432, Subcortical laminar heterotopia, MIM# 607432, MONDO:0011830; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2888 GRIN2B Zornitza Stark Phenotypes for gene: GRIN2B were changed from Mental retardation, autosomal dominant 6, MIM# 613970; Epileptic encephalopathy, early infantile, 27, MIM# 616139 to Mental retardation, autosomal dominant 6, MIM# 613970; Epileptic encephalopathy, early infantile, 27, MIM# 616139
Intellectual disability syndromic and non-syndromic v0.2888 GRIN2B Zornitza Stark Phenotypes for gene: GRIN2B were changed from to Mental retardation, autosomal dominant 6, MIM# 613970; Epileptic encephalopathy, early infantile, 27, MIM# 616139
Intellectual disability syndromic and non-syndromic v0.2885 GRIN2B Zornitza Stark reviewed gene: GRIN2B: Rating: GREEN; Mode of pathogenicity: None; Publications: 28377535; Phenotypes: Mental retardation, autosomal dominant 6, MIM# 613970, Epileptic encephalopathy, early infantile, 27, MIM# 616139; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2873 CRADD Zornitza Stark Phenotypes for gene: CRADD were changed from to Mental retardation, autosomal recessive 34, with variant lissencephaly, MIM# 614499
Intellectual disability syndromic and non-syndromic v0.2870 CRADD Zornitza Stark reviewed gene: CRADD: Rating: GREEN; Mode of pathogenicity: None; Publications: 27773430; Phenotypes: Mental retardation, autosomal recessive 34, with variant lissencephaly, MIM# 614499; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2870 TMTC3 Zornitza Stark Phenotypes for gene: TMTC3 were changed from to Lissencephaly 8 (MIM#617255)
Intellectual disability syndromic and non-syndromic v0.2867 TMTC3 Zornitza Stark reviewed gene: TMTC3: Rating: GREEN; Mode of pathogenicity: None; Publications: 27773428, 28973161; Phenotypes: Lissencephaly 8 (MIM#617255); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2864 GABRG2 Zornitza Stark Phenotypes for gene: GABRG2 were changed from to Epileptic encephalopathy, early infantile, 74 618396; Epilepsy, generalized, with febrile seizures plus, type 3 607681
Intellectual disability syndromic and non-syndromic v0.2861 GABRG2 Zornitza Stark reviewed gene: GABRG2: Rating: GREEN; Mode of pathogenicity: None; Publications: 11326274, 11326275, 27864268; Phenotypes: Epileptic encephalopathy, early infantile, 74 618396, Epilepsy, generalized, with febrile seizures plus, type 3 607681; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2861 GABRB3 Zornitza Stark Phenotypes for gene: GABRB3 were changed from to Epileptic encephalopathy, early infantile, 43, MIM# 617113
Intellectual disability syndromic and non-syndromic v0.2858 GABRB3 Zornitza Stark reviewed gene: GABRB3: Rating: GREEN; Mode of pathogenicity: None; Publications: 23934111, 27476654; Phenotypes: Epileptic encephalopathy, early infantile, 43, MIM# 617113; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2854 KAT5 Zornitza Stark Phenotypes for gene: KAT5 were changed from to Severe global developmental delay; Intellectual disability; Seizures; Microcephaly; Behavioral abnormality; Sleep disturbance; Morphological abnormality of the central nervous system; Short stature; Oral cleft; Abnormality of the face
Intellectual disability syndromic and non-syndromic v0.2849 KAT5 Konstantinos Varvagiannis reviewed gene: KAT5: Rating: GREEN; Mode of pathogenicity: Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments; Publications: 32822602; Phenotypes: Severe global developmental delay, Intellectual disability, Seizures, Microcephaly, Behavioral abnormality, Sleep disturbance, Morphological abnormality of the central nervous system, Short stature, Oral cleft, Abnormality of the face; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Intellectual disability syndromic and non-syndromic v0.2849 LMBRD2 Konstantinos Varvagiannis gene: LMBRD2 was added
gene: LMBRD2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: LMBRD2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: LMBRD2 were set to 32820033; https://doi.org/10.1101/797787
Phenotypes for gene: LMBRD2 were set to Global developmental delay; Intellectual disability; Microcephaly; Seizures; Abnormality of nervous system morphology; Abnormality of the eye
Penetrance for gene: LMBRD2 were set to unknown
Mode of pathogenicity for gene: LMBRD2 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: LMBRD2 was set to AMBER
Added comment: You may consider inclusion with green (13 individuals with dn missense SNVs overall, overlapping features for 10 with available phenotype / a recurring variant has been identified in 2 different studies) or amber rating (role of the gene not known, no variant studies, animal model probably not available).

► Malhotra et al (2020 - PMID: 32820033) report on 10 unrelated individuals with de novo missense LMBRD2 variants.

Features included DD (9/10), ID (6/8 of relevant age), microcephaly (7/10), seizures (5/10 - >=3 different variants), structural brain abnormalities (e.g. thin CC in 6/9), highly variable ocular abnormalities (5/10) and dysmorphic features in some (7/10 - nonspecific).

All had variable prior non-diagnostic genetic tests (CMA, gene panel, mendeliome, karyotype). WES/WGS revealed LMBRD2 missense variants, in all cases de novo. A single individual had additional variants with weaker evidence of pathogenicity.

5 unique missense SNVs and 2 recurrent ones (NM_001007527:c.367T>C - p.Trp123Arg / c.1448G>A - p.Arg483His) were identified. These occurred in different exons. Variants were not present in gnomAD and all had several in silico predictions in favor of a deleterious effect.

There was phenotypic variability among individuals with the same variant (e.g. seizures in 1/3 and microchephaly in 2/3 of those harboring R483H).

The gene has a pLI of 0 (although o/e ranges from 0.23 to 0.55), %HI of 15.13 and z-score of 2.27. The authors presume that haploinsufficiency may not apply, and consider a gain-of-function/dominant-negative effect more likely.

As the authors comment LMBRD2 (LMBR1 domain containing 2) encodes a membrane bound protein with poorly described function. It is widely expressed across tissues with notable expression in human brain (also in Drosophila, or Xenopus laevis). It displays high interspecies conservation.

It has been suggested (Paek et al - PMID: 28388415) that LMBRD2 is a potential regulator of β2 adrenoreceptor signalling through involvement in GPCR signalling.

► Kaplanis et al (2020 - https://doi.org/10.1101/797787) in a dataset of 31058 parent-offspring trios (WES) previously identified 3 individuals with developmental disorder, harboring c.1448G>A - p.Arg483His. These individuals (1 from the DDD study, and 2 GeneDx patients) appear in Decipher. [ https://decipher.sanger.ac.uk/ddd/research-variant/40e17c78cc9655a6721006fc1e0c98db/overview ]. The preprint by Kaplanis et al is cited by Malhotra et al, with Arg483His reported in 6 patients overall in both studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2843 TAOK1 Zornitza Stark Phenotypes for gene: TAOK1 were changed from to Intellectual disability; hypotonia; macrocephaly
Intellectual disability syndromic and non-syndromic v0.2840 TAOK1 Sue White commented on gene: TAOK1: Monoallelic de novo variants reported in 8 individuals with nonspecific phenotype of intellectual disability and hypotonia. Most were LOF, 2 missense. 3 had macrocephaly.
Intellectual disability syndromic and non-syndromic v0.2836 TAF1C Konstantinos Varvagiannis gene: TAF1C was added
gene: TAF1C was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TAF1C was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TAF1C were set to 32779182
Phenotypes for gene: TAF1C were set to Global developmental delay; Intellectual disability; Spasticity; Strabismus; Seizures; Abnormality of nervous system morphology
Penetrance for gene: TAF1C were set to Complete
Review for gene: TAF1C was set to AMBER
Added comment: Knuutinen et al (2020 - PMID: 32779182) report on 2 individuals from 2 consanguineous families, homozygous for TAF1C missense variants.

Both presented with an early onset neurological phenotype with severe global DD, ID (2/2 - moderate and profound), spasticity (2/2), ophthalmic findings (strabismus 2/2, nystagmus 1/2). Epilepsy, abnormal brain MRI (cerebral and cerebellar atrophy and white matter hyperintensities) as well and additional findings were reported in one (always the same individual).

Following a normal CMA, exome in the first case revealed a homozygous missense SNV (NM_005679.3:c.1165C>T / p.Arg389Cys) supported by in silico predictions. mRNA and protein levels were substantially reduced in fibroblasts from this subject. Only the patient and parents were tested for the variant but not 3 unaffected sibs (fig1).

The second individual was homozygous for another missense variant (p.Arg405Cys) also supported by in silico predictions. The girl was the single affected person within the family with an unaffected sib and parents heterozygous for the variant. Several other unaffected relatives in the extended pedigree were either carriers for this variant or homozygous for the wt allele.

TAF1C encodes the TATA-box binding protein associated factor (TAF) RNA polymerase I subunit.

RNA polymerase I (Pol I) transcribes genes to produce rRNA. For Pol I to initiate transcription, two transcription factors are required : UBF (upstream binding factor encoded by UBTF) and SL1 (selectivity factor 1). The latter is formed by TBP (TATA-binding protein) and 3 Pol I-specific TBP-associated factors (TAFs).

A recurrent de novo missense variant in UBTF (encoding the other Pol I transcription factor) causes a disorder with highly similar features. The specific variant acts through a gain-of-function mechanism (and not by LoF which appears to apply for TAF1C based on expression data).

The authors hypothesize that altered Pol I activity and resulting ribosomal stress could cause the microcephaly and leukodystrophy (both reported in 1 - the same - individual).

As a result, TAF1C may be considered for inclusion in the ID panel with amber rating pending further evidence.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2833 FAM50A Konstantinos Varvagiannis gene: FAM50A was added
gene: FAM50A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: FAM50A was set to X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Publications for gene: FAM50A were set to 32703943
Phenotypes for gene: FAM50A were set to Mental retardation syndrome, X-linked, Armfield type (MIM #300261)
Penetrance for gene: FAM50A were set to unknown
Review for gene: FAM50A was set to GREEN
Added comment: Lee et al (2020 - PMID: 32703943) provide evidence that Armfield X-Linked intellectual disability syndrome is caused by monoallelic FAM50A pathogenic variants. The current review is based only on this reference.

The authors provide clinical details on 6 affected individuals from 5 families.

Features included postnatal growth delay, DD and ID (6/6 - also evident for those without formal IQ assesment), seizures (3/6 from 2 families), prominent forehead with presence of other facial features and variable head circumference (5th to >97th %le), ocular anomalies (5/6 - strabismus/nystagmus/Axenfeld-Rieger), cardiac (3/6 - ASD/Fallot) and genitourinary anomalies (3/6).

In the first of these families (Armfield et al 1999 - PMID: 10398235), linkage analysis followed by additional studies (Sanger, NGS of 718 genes on chrX, X-exome NGS - several refs provided) allowed the identification of a FAM50A variant. Variants in other families were identified by singleton (1 fam) or trio-ES (3 fam).

In affected individuals from 3 families, the variant had occurred de novo. Carrier females in the other families were unaffected (based on pedigrees and/or the original publication). XCI was rather biased in most obligate carrier females from the 1st family (although this ranged from 95:5 to 60:40).

Missense variants were reported in all affected subjects incl. Trp206Gly, Asp255Gly, Asp255Asn (dn), Glu254Gly (dn), Arg273Trp (dn) (NM_004699.3).

Previous studies have demonstrated that FAM50A has ubiquitous expression in human fetal and adult tissues (incl. brain in fetal ones).

Immunostaining suggests a nuclear localization for the protein (NIH/3T3 cells). Comparison of protein levels in LCLs from affected males and controls did not demonstrate significant differences. Protein localization for 3 variants (transfection of COS-7 cells) was shown to be similar to wt.

Complementation studies in zebrafish provided evidence that the identified variants confer partial loss of function (rescue of the morpholino phenotype with co-injection of wt but not mt mRNA). The zebrafish ko model seemed to recapitulate the abnormal development of cephalic structures and was indicative of diminished/defective neurogenesis. Transcriptional dysregulation was demonstrated in zebrafish (altered levels and mis-splicing). Upregulation of spliceosome effectors was demonstrated in ko zebrafish.

Similarly, mRNA expression and splicing defects were demonstrated in LCLs from affected individuals. FAM50A pulldown followed by mass spectrometry in transfected HEK293T cells demonstrated enrichment of binding proteins involved in RNA processing and co-immunoprecipitation assays (transfected U-87 cells) suggested that FAM50A interacts with spliceosome U5 and C-complex proteins.

Overall aberrant spliceosome C-complex function is suggested as the underlying pathogenetic mechanism.

Several other neurodevelopmental syndromes are caused by variants in genes encoding C-complex affiliated proteins (incl. EFTUD2, EIF4A3, THOC2, etc.).

Please consider inclusion in the ID panel with green rating and epilepsy panel with amber (seizures in individuals from 2 families).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2828 HYLS1 Zornitza Stark changed review comment from: Given that generally most affected individuals die in utero or shortly after birth, this is probably not the right panel for this gene.; to: Single family reported with Joubert phenotype, generally most affected individuals with hydrolethalus die in utero or shortly after birth so would not present with ID. Note founder variant in Finnish population associated with the hydrolethalus phenotype.
Intellectual disability syndromic and non-syndromic v0.2823 BCOR Zornitza Stark Phenotypes for gene: BCOR were changed from to Microphthalmia, syndromic 2, MIM# 300166; Oculofaciocardiodental syndrome; Lenz microphthalmia
Intellectual disability syndromic and non-syndromic v0.2820 BCOR Zornitza Stark reviewed gene: BCOR: Rating: GREEN; Mode of pathogenicity: None; Publications: 29974297; Phenotypes: Microphthalmia, syndromic 2, MIM# 300166, Oculofaciocardiodental syndrome, Lenz microphthalmia; Mode of inheritance: X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Intellectual disability syndromic and non-syndromic v0.2813 PIGQ Konstantinos Varvagiannis gene: PIGQ was added
gene: PIGQ was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PIGQ was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PIGQ were set to 32588908; 24463883; 25558065; 31148362
Phenotypes for gene: PIGQ were set to Epileptic encephalopathy, early infantile, 77 (MIM #618548)
Penetrance for gene: PIGQ were set to Complete
Review for gene: PIGQ was set to GREEN
Added comment: Homozygous or compound heterozygous mutations in PIGQ cause Epileptic encephalopathy, early infantile, 77 (MIM #618548).

Johnstone et al (2020 - PMID: 32588908) describe the phenotype of 7 children (from 6 families) with biallelic PIGQ pathogenic variants. The authors also review the phenotype of 3 subjects previously reported in the literature (by Martin et al, Alazami et al, Starr et al - respective PMIDs: 24463883, 25558065, 31148362).

Affected individuals displayed severe to profound global DD/ID and seizures with onset in the first year of life. There were variable other features incl. - among others - genitourinary, cardiac, skeletal, ophthalmological anomalies, gastrointestinal issues. Within the cohort there was significant morbidity/mortality.

PIGQ encodes phosphatidylinositol glycan anchor biosynthesis class Q protein, playing a role (early) in the biosynthesis of the GPI-anchor. Several genes in the GPI biosynthesis pathway cause multi-system disease with DD/ID and seizures. Flow cytometry has been used in individuals with PIGQ-related disorder. Serum ALP was elevated in some (4) although - as the authors comment - elevations are more typical in disorders affecting later steps of GPI biosynthesis.

More than 10 variants have been reported to date (missense / pLoF).

Overall PIGQ can be considered for green rating in both ID and epilepsy gene panels.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2811 HPDL Crystle Lee gene: HPDL was added
gene: HPDL was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: HPDL was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: HPDL were set to 32707086
Phenotypes for gene: HPDL were set to Progressive neurological disorder
Review for gene: HPDL was set to GREEN
Added comment: Biallelic variants reported in 13 families with a neurodegenerative disease ranging from neonatal encephalopathy to adolescent-onset spastic paraplegia
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.2807 PJA1 Zornitza Stark gene: PJA1 was added
gene: PJA1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PJA1 was set to X-LINKED: hemizygous mutation in males, biallelic mutations in females
Publications for gene: PJA1 were set to 32530565
Phenotypes for gene: PJA1 were set to Intellectual disability; trigonocephaly
Review for gene: PJA1 was set to AMBER
Added comment: Recurrent variant, p.Arg376Cys, reported in 7 Japanese individuals, supportive mouse model. Individuals shared a common haplotype, suggestive of founder effect.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2805 NARS Konstantinos Varvagiannis changed review comment from: [Please note that HGNC Approved Gene Symbol for this gene is NARS1]

Manole et al (2020 - PMID: 32738225) provide evidence that both biallelic and monoallelic (de novo) pathogenic NARS1 variants cause a neurodevelopmental disorder. In total 32 individuals from 21 families are reported, with biallelic variants identified in individuals from 13 families and de novo in 8 families.

Similar features were reported for AR/AD occurrences of the disorder and included of microcephaly (90% - most often primary), epilepsy (23/32 or 74% - variable semiology incl. partial/myoclonic/generalized tonic-clonic seizures), DD and ID (as a universal feature), abnormal tone in several (hypotonia/spasticity), ataxia, demyelinating peripheral neuropathy (in 3 or more for each inheritance mode - or a total of 25%). Some individuals had dysmorphic features.

NARS1 encodes an aminoacyl-tRNA synthetase (ARS) [asparaginyl-tRNA synthetase 1]. Aminoacyl-tRNA synthetases constitute a family of enzymes catalyzing attachment of amino-acids to their cognate tRNAs. As the authors comment, mutations in genes encoding several other ARSs result in neurological disorders ranging from peripheral neuropathy to severe multi-systemic NDD. Dominant, recessive or both modes for inheritance for mutations in the same gene (e.g. AARS1, YARS1, MARS1, etc) have been reported.

Some variants were recurrent, e.g. the c.1600C>T / p.Arg534* which occurred in 6 families as a de novo event or c.1633C>T p.Arg545Cys (homozygous in 6 families). 3 different variants were reported to have occured de novo (c.965G>T - p.Arg322Leu, c.1525G>A - p.Gly509Ser, p.Arg534*) with several other variants identified in hmz/compound htz individuals. A single SNV (c.1067A>C - p.Asp356Ala) was suggested to be acting as modifier and pathogenic only when in trans with a severe variant. [NM_004539.4 used as RefSeq for all].

The authors provide several lines of evidence for a partial loss-of-function effect (e.g. reduction in mRNA expression, enzyme levels and activity in fibroblasts or iNPCs) underlying pathogenicity of the variants identified in individuals with biallelic variants. A gain-of-function (dominant-negative) effect is proposed for de novo variants (such effect also demonstrated for the p.Arg534* in a zebrafish model).

As also Manole et al suggest, NARS1 can be considered for inclusion in gene panels for DD/ID, epilepsy and/or demyelinating neuropathy.
Sources: Literature; to: [Please note that HGNC Approved Gene Symbol for this gene is NARS1]

Manole et al (2020 - PMID: 32738225) provide evidence that both biallelic and monoallelic (de novo) pathogenic NARS1 variants cause a neurodevelopmental disorder. In total 32 individuals from 21 families are reported, with biallelic variants identified in individuals from 13 families and de novo in 8 families.

Similar features were reported for AR/AD occurrences of the disorder and included microcephaly (90% - most often primary), epilepsy (23/32 or 74% - variable semiology incl. partial/myoclonic/generalized tonic-clonic seizures), DD and ID (as a universal feature), abnormal tone in several (hypotonia/spasticity), ataxia, demyelinating peripheral neuropathy (in 3 or more for each inheritance mode - or a total of 25%). Some individuals had dysmorphic features.

NARS1 encodes an aminoacyl-tRNA synthetase (ARS) [asparaginyl-tRNA synthetase 1]. Aminoacyl-tRNA synthetases constitute a family of enzymes catalyzing attachment of amino-acids to their cognate tRNAs. As the authors comment, mutations in genes encoding several other ARSs result in neurological disorders ranging from peripheral neuropathy to severe multi-systemic NDD. Dominant, recessive or both modes for inheritance for mutations in the same gene (e.g. AARS1, YARS1, MARS1, etc) have been reported.

Some variants were recurrent, e.g. the c.1600C>T / p.Arg534* which occurred in 6 families as a de novo event or c.1633C>T p.Arg545Cys (homozygous in 6 families). 3 different variants were reported to have occured de novo (c.965G>T - p.Arg322Leu, c.1525G>A - p.Gly509Ser, p.Arg534*) with several other variants identified in hmz/compound htz individuals. A single SNV (c.1067A>C - p.Asp356Ala) was suggested to be acting as modifier and pathogenic only when in trans with a severe variant. [NM_004539.4 used as RefSeq for all].

The authors provide several lines of evidence for a partial loss-of-function effect (e.g. reduction in mRNA expression, enzyme levels and activity in fibroblasts or iNPCs) underlying pathogenicity of the variants identified in individuals with biallelic variants. A gain-of-function (dominant-negative) effect is proposed for de novo variants (such effect also demonstrated for the p.Arg534* in a zebrafish model).

As also Manole et al suggest, NARS1 can be considered for inclusion in gene panels for DD/ID, epilepsy and/or demyelinating neuropathy.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2805 NARS Konstantinos Varvagiannis gene: NARS was added
gene: NARS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: NARS was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: NARS were set to 32738225
Phenotypes for gene: NARS were set to Abnormal muscle tone; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Ataxia; Abnormality of the face; Demyelinating peripheral neuropathy
Penetrance for gene: NARS were set to Complete
Review for gene: NARS was set to GREEN
Added comment: [Please note that HGNC Approved Gene Symbol for this gene is NARS1]

Manole et al (2020 - PMID: 32738225) provide evidence that both biallelic and monoallelic (de novo) pathogenic NARS1 variants cause a neurodevelopmental disorder. In total 32 individuals from 21 families are reported, with biallelic variants identified in individuals from 13 families and de novo in 8 families.

Similar features were reported for AR/AD occurrences of the disorder and included of microcephaly (90% - most often primary), epilepsy (23/32 or 74% - variable semiology incl. partial/myoclonic/generalized tonic-clonic seizures), DD and ID (as a universal feature), abnormal tone in several (hypotonia/spasticity), ataxia, demyelinating peripheral neuropathy (in 3 or more for each inheritance mode - or a total of 25%). Some individuals had dysmorphic features.

NARS1 encodes an aminoacyl-tRNA synthetase (ARS) [asparaginyl-tRNA synthetase 1]. Aminoacyl-tRNA synthetases constitute a family of enzymes catalyzing attachment of amino-acids to their cognate tRNAs. As the authors comment, mutations in genes encoding several other ARSs result in neurological disorders ranging from peripheral neuropathy to severe multi-systemic NDD. Dominant, recessive or both modes for inheritance for mutations in the same gene (e.g. AARS1, YARS1, MARS1, etc) have been reported.

Some variants were recurrent, e.g. the c.1600C>T / p.Arg534* which occurred in 6 families as a de novo event or c.1633C>T p.Arg545Cys (homozygous in 6 families). 3 different variants were reported to have occured de novo (c.965G>T - p.Arg322Leu, c.1525G>A - p.Gly509Ser, p.Arg534*) with several other variants identified in hmz/compound htz individuals. A single SNV (c.1067A>C - p.Asp356Ala) was suggested to be acting as modifier and pathogenic only when in trans with a severe variant. [NM_004539.4 used as RefSeq for all].

The authors provide several lines of evidence for a partial loss-of-function effect (e.g. reduction in mRNA expression, enzyme levels and activity in fibroblasts or iNPCs) underlying pathogenicity of the variants identified in individuals with biallelic variants. A gain-of-function (dominant-negative) effect is proposed for de novo variants (such effect also demonstrated for the p.Arg534* in a zebrafish model).

As also Manole et al suggest, NARS1 can be considered for inclusion in gene panels for DD/ID, epilepsy and/or demyelinating neuropathy.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2804 ZNF407 Konstantinos Varvagiannis gene: ZNF407 was added
gene: ZNF407 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ZNF407 was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: ZNF407 were set to 24907849; 32737394; 23195952
Phenotypes for gene: ZNF407 were set to Global developmental delay; Intellectual disability
Penetrance for gene: ZNF407 were set to unknown
Review for gene: ZNF407 was set to AMBER
Added comment: You may consider inclusion of this gene probably with amber rating (or green if the evidence for biallelic variants is considered sufficient).

Biallelic variants:

- Kambouris et al. (2014 - PMID: 24907849) described 2 brothers with severe DD and ID, born to first cousin parents. Homozygosity mapping, following other non-diagnostic investigations (incl. aCGH), revealed 4 major homozygosity intervals. Exome sequencing in one identified 5 variants within these intervals, ZNF407 (c.5054C>G, p.Ser1685Trp) being the best candidate, supported also by segregation studies. The authors commented that zinc finger proteins act as transcriptional regulators, with mutations in genes encoding for other zinc finger proteins interfering with normal brain development.

- Zahra et al. (2020 - PMID: 32737394) report on 7 affected individuals (from 3 families) homozygous or compound heterozygous for ZNF407 variants. Features included hypotonia, DD and ID (in all) and variable occurrence of short stature (6/6), microcephaly (in at least 5), behavioural, visual problems and deafness. Linkage analysis in the first family revealed a 4.4 Mb shared homozygosity region and exome (30x) revealed a 3-bp duplication, confirmed by Sanger sequencing and segregating with the disease (NM_001146189:c.2814_2816dup, p.Val939dup). Affected subjects from the 2 other families were each found to be homozygous (c.2405G>T) or compound heterozygous (c.2884C>G, c.3642G>C) for other variants. Segregation was compatible in all families. Other studies were not performed. The authors comment than only the 3-bp duplication fullfilled ACMG criteria for classification as LP, the other variants being all formally classified as VUS (also due to in silico predictions predicting a LB effect). In addition, while several features such as DD/ID and short stature appeared to be frequent among all patients reported, Zahra et all comment that there was partial clinical overlap with the sibs described by Kambouris et al (additional variants?).


Monoallelic disruption of ZNF407:

- Ren et al (2013 - PMID: 23195952) described an 8 y.o. boy with ID and ASD. The boy was found to harbor a de novo translocation between chromosomes 3 and 18 [46,XY,t(3;18)(p13;q22.3)]. Array CGH did not reveal any P/LP CNV. Delineation of the breakpoints (FISH, long-range PCR) revealed that the chr18 breakpoint disrupted intron 3 of ZNF407 (isoform 1) with the other breakpoint within a gene-free region of exon 3. There was a loss of 4-8 nt in chr18 and 2-6 in chr3. Sequencing of ZNF407 did not reveal additional variants. RNA isolation in blood followed by RT-PCR studied expression of all 3 ZNF407 isoforms (the intronic region being shared by isoforms 1 and 2). Expression of isoform 1 was shown to be significantly reduced compared to controls. Isoform 2 was undetectable (in blood) while isoform 3 expression was similar to controls. Sequencing of 105 additional patients with similar clinical presentation (ID & ASD) revealed 2 further individuals with de novo missense variants.

- Based on the discussion by Kambouris et al (PMID: 24907849 - cited literature not here reviewed) ZNF407 may be deleted in patients with congenital aural atresia due to deletion of a critical region of 18q22.3 (though TSHZ1 is responsible for this phenotype) or 18q- although such deletions span several other genes (cited PMID: 16639285). In one case the breakpoint was shown to be disrupting ZNF407 (cited PMID: 24092497).

- The denovo db and Decipher (research variant tab) list few individuals with de novo ZNF407 SNVs although these do not seem to allow conclusions.

https://denovo-db.gs.washington.edu/denovo-db/QueryVariantServlet?searchBy=Gene&target=ZNF407
https://decipher.sanger.ac.uk/search/ddd-research-variants/results?q=znf407
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2803 MAPK1 Konstantinos Varvagiannis gene: MAPK1 was added
gene: MAPK1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MAPK1 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: MAPK1 were set to 32721402
Phenotypes for gene: MAPK1 were set to Global developmental delay; Intellectual disability; Behavioral abnormality; Growth delay; Abnormality of the face; Abnormality of the neck; Abnormality of the cardiovascular system; Abnormality of the skin
Penetrance for gene: MAPK1 were set to unknown
Mode of pathogenicity for gene: MAPK1 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: MAPK1 was set to GREEN
Added comment: Motta et al (2020 - PMID: 32721402) report on 7 unrelated individuals harboring de novo missense MAPK1 pathogenic variants.

The phenotype corresponded to a neurodevelopmental disorder and - as the authors comment - consistently included DD, ID , behavioral problems. Postnatal growth delay was observed in approximately half. Hypertelorism, ptosis, downslant of palpebral fissures, wide nasal bridge as low-set/posteriorly rotated ears were among the facial features observed (each in 3 or more subjects within this cohort). Together with short/webbed neck and abnormalities of skin (lentigines / CAL spots) and growth delay these led to clinical suspicion of Noonan s. or disorder of the same pathway in some. Congenital heart defects (ASD, mitral valve insufficiency, though not cardiomyopathy) occurred in 4/7. Bleeding diathesis and lymphedema were reported only once.

MAPK1 encodes the mitogen-activated protein kinase 1 (also known as ERK2) a serine/threonine kinase of the RAS-RAF-MEK-(MAPK/)ERK pathway.

MAPK1 de novo variants were identified in all individuals following trio exome sequencing (and extensive previous genetic investigations which were non-diagnostic).

The distribution of variants, as well as in silico/vitro/vivo studies suggest a GoF effect (boosted signal through the MAPK cascade. MAPK signaling also upregulated in Noonan syndrome).

The authors comment that screening of 267 additional individuals with suspected RASopathy (without mutations in previously implicated genes) did not reveal other MAPK1 variants.

Overall this gene can be considered for inclusion in the ID panel with green rating.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2803 ASPM Zornitza Stark Phenotypes for gene: ASPM were changed from to Microcephaly 5, primary, autosomal recessive, MIM#608716
Intellectual disability syndromic and non-syndromic v0.2800 ASPM Zornitza Stark reviewed gene: ASPM: Rating: GREEN; Mode of pathogenicity: None; Publications: 29243349, 19028728; Phenotypes: Microcephaly 5, primary, autosomal recessive, MIM#608716; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2797 EEF1A2 Zornitza Stark Phenotypes for gene: EEF1A2 were changed from to Epileptic encephalopathy, early infantile, 33, MIM# 616409; Mental retardation, autosomal dominant 38, MIM# 616393
Intellectual disability syndromic and non-syndromic v0.2793 EEF1A2 Zornitza Stark reviewed gene: EEF1A2: Rating: GREEN; Mode of pathogenicity: Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments; Publications: 32160274; Phenotypes: Epileptic encephalopathy, early infantile, 33, MIM# 616409, Mental retardation, autosomal dominant 38, MIM# 616393; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2793 TASP1 Zornitza Stark Phenotypes for gene: TASP1 were changed from Developmental delay; microcephaly; dysmorphic features; congenital abnormalities to Developmental delay; microcephaly; dysmorphic features; congenital abnormalities; Suleiman-El-Hattab syndrome, MIM#618950
Intellectual disability syndromic and non-syndromic v0.2792 TASP1 Zornitza Stark edited their review of gene: TASP1: Changed phenotypes: Developmental delay, microcephaly, dysmorphic features, congenital abnormalities, Suleiman-El-Hattab syndrome, MIM#618950
Intellectual disability syndromic and non-syndromic v0.2792 LARS Zornitza Stark Phenotypes for gene: LARS were changed from Infantile liver failure syndrome 1, MIM# 615438 to Infantile liver failure syndrome 1, MIM# 615438; Seizures; Intellectual disability; Encephalopathy
Intellectual disability syndromic and non-syndromic v0.2790 LARS Konstantinos Varvagiannis gene: LARS was added
gene: LARS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: LARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: LARS were set to 32699352
Phenotypes for gene: LARS were set to Infantile liver failure syndrome 1, MIM# 615438
Penetrance for gene: LARS were set to Complete
Review for gene: LARS was set to GREEN
Added comment: Please consider inclusion with amber/green rating in the current panel.

Biallelic pathogenic LARS1 variants cause Infantile liver failure syndrome 1, MIM# 615438.

Lenz et al (2020 - PMID: 32699352) review the phenotype of 25 affected individuals from 15 families.

Seizures occurred in 19/24 and were commonly associated with infections. Encephalopathic episodes (in 13 patients) accompanied by seizures up to status epilepticus occurred independently of hepatic decompensation.

In addition 22/24 presented with neurodevelopmental delay. The authors comment that cognitive impairment was present in 13/17 individuals (mild-severe) whereas most presented with learning disabilities.

These patients will most likely investigated for their liver disease (although presentation was highly variable and/or very mild in few).

The gene encodes a cytoplasmic amino-acyl tRNA synthetase (ARS) with neurologic manifestations observed in almost all patients (and seizures / DD and ID common to other disorders due to mutations in other genes encoding for ARSs).

Please note that the HGNC approved symbol for this gene is LARS1.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2783 MORC2 Konstantinos Varvagiannis gene: MORC2 was added
gene: MORC2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MORC2 was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: MORC2 were set to https://doi.org/10.1016/j.ajhg.2020.06.013
Phenotypes for gene: MORC2 were set to Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688
Penetrance for gene: MORC2 were set to unknown
Mode of pathogenicity for gene: MORC2 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: MORC2 was set to GREEN
Added comment: The current review is based on a recent report by Sacoto et al (2020 - https://doi.org/10.1016/j.ajhg.2020.06.013).

While several previous studies focused on the phenotype of axonal motor and senory neuropathy in individuals with heterozygous MORC2 pathogenic variants (Charcot-Marie-Tooth disease, axonal, type 2Z, MIM #616688) some of them presented among others with hypotonia, muscle weakness, intellectual disability, microcephaly or hearing loss [refs provided by Sacoto et al - learning disabilities (in some patients) also listed in OMIM's clinical synopsis].

Sacoto et al present a cohort of 20 individuals having genetic testing for developmental delay or growth failure (with a single one for a diagnosis of sensorimotor neuropathy).

Overlapping features included DD, ID (18/20 - mild to severe), short stature (18/20), microcephaly (15/20) and variable craniofacial dysmorphisms. The authors comment that features suggestive of neuropathy (weakness, hyporeflexia, abnormal EMG/NCS) were frequent but not the predominant complaint. EMG/NCS abnormalities were abnormal in 6 out of 10 subjects investigated in this cohort. Other findings included brain MRI abnormalities (12/18 - in 5/18 Leigh-like lesions), hearing loss (11/19) and pigmentary retinopathy in few (5).

Affected subjects were found to harbor in all cases missense variants in the ATPase module of MORC2 [residues 1 to 494 - NM_001303256.1 - the module consists of an ATPase domain (aa 1-265), a transducer S5-like domain (266-494) and a coiled-coiled domain (CC1 - aa 282-361)].

Variants had occured mostly as de novo events although inheritance from a similarly affected parent was also reported.

Some of them were recurring within this cohort and/or the literature eg. c.79G>A/p.Glu27Lys (x5), c.260C>T/p.Ser87Leu (x2), c.394C>T/p.Arg132Cys (4x), c.1164C>G/p.Ser388Arg (x2), c.1181A>G/p.Tyr394Cys (x3).

MORC2 encodes an ATPase involved in chromatin remodeling, DNA repair and transcriptional regulation. Chromatin remodeling and epigenetic silencing by MORC2 is mediated by the HUSH (Human Silencing Hub) complex. Functional studies (MORC2-knockout HeLa cells harboring a HUSH-sensitive GFP reporter were transduced with wt or mt MORC2 followed by measurement of reporter repression) supported the deleterious effect of most variants known at the time (hyperactivation of HUSH-mediating silencing, in line with previous observations).

Overall this gene can be considered for inclusion in the ID panel with green rating. Also other gene panels (e.g. for short stature, microcephaly, hearing loss, pigmentary retinopathy, etc) if it meets the respective criteria for inclusion.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2771 GRM7 Zornitza Stark Phenotypes for gene: GRM7 were changed from Epilepsy, microcephaly, developmental delay to Epilepsy, microcephaly, developmental delay; neurodevelopmental disorder with seizures, hypotonia, and brain imaging abnormalities (NEDSHBA), MIM#618922
Intellectual disability syndromic and non-syndromic v0.2770 GRM7 Zornitza Stark edited their review of gene: GRM7: Changed phenotypes: Epilepsy, microcephaly, developmental delay, neurodevelopmental disorder with seizures, hypotonia, and brain imaging abnormalities (NEDSHBA), MIM#618922
Intellectual disability syndromic and non-syndromic v0.2750 CNPY3 Konstantinos Varvagiannis gene: CNPY3 was added
gene: CNPY3 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CNPY3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CNPY3 were set to 29394991; 30237576
Phenotypes for gene: CNPY3 were set to Epileptic encephalopathy, early infantile, 60 (MIM 617929)
Penetrance for gene: CNPY3 were set to Complete
Review for gene: CNPY3 was set to GREEN
Added comment: Biallelic CNPY3 mutations cause Epileptic encephalopathy, early infantile, 60 (MIM 617929).

The phenotype including among others hypotonia, intractable seizures, DD and ID has been first reported by Mutoh et al (2018 - PMID: 29394991) in 3 subjects from 2 families. Evidence was provided for the role of the gene (incl. mouse model) and pathogenicity of the identified variants (resulting in LoF).

Another subject with similar features of hypotonia, DD, intractable epilepsy, feeding problems has been described briefly by Maddirevula et al (2019 - PMID: 30237576).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2750 KIF21B Konstantinos Varvagiannis gene: KIF21B was added
gene: KIF21B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: KIF21B was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: KIF21B were set to 32415109
Phenotypes for gene: KIF21B were set to Global developmental delay; Intellectual disability; Abnormality of brain morphology; Microcephaly
Penetrance for gene: KIF21B were set to unknown
Mode of pathogenicity for gene: KIF21B was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: KIF21B was set to GREEN
Added comment: Asselin et al (2020 - PMID: 32415109) report on 4 individuals with KIF21B pathogenic variants. DD/ID (borderline intellectual functioning to severe ID) was a feature in all. Variable other findings included brain malformations (CCA) and microcephaly. 3 missense variants and a 4-bp insertion were identified, in 3 cases as de novo events while in a single subject the variant was inherited from the father who was also affected. The authors provide evidence for a role of KIF21B in the regulation of processes involved in cortical development and deleterious effect of the missense variants impeding neuronal migration and kinesin autoinhibition. Phenotypes specific to variants (e.g. CCA or microcephaly) were recapitulated in animal models. Missense variants are thought to exert a gain-of-function effect. As commented on, the 4-bp duplication (/frameshift) variant might not be pathogenic. In blood sample from the respective individual, RT-qPCR analysis suggested that haploinsufficiency (NMD) applies. Although Kif21b haploinsufficiency in mice was shown to lead to impaired neuronal positioning, the gene might partially tolerate LoF variants as also suggested by 28 such variants in gnomAD. Homozygous Kif21b ko mice display severe morphological abnormalities, partial loss of commissural fibers, cognitive deficits and altered synaptic transmission (several refs to previous studies provided by the authors).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2750 TBC1D2B Konstantinos Varvagiannis gene: TBC1D2B was added
gene: TBC1D2B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TBC1D2B was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TBC1D2B were set to 32623794
Phenotypes for gene: TBC1D2B were set to Global developmental delay; Intellectual disability; Seizures; Gingival overgrowth; Behavioral abnormality; Abnormality of the mandible; Abnormality of brain morphology; Abnormality of the eye; Hearing abnormality
Penetrance for gene: TBC1D2B were set to Complete
Review for gene: TBC1D2B was set to AMBER
Added comment: Harms et al (2020 - PMID: 32623794) report on 3 unrelated individuals with biallelic pLoF TBC1D2B variants.

Features included cognitive impairment (mild ID in one case, regression at the age of 12y in another, hypotonia and delayed milestones in a third aged 8m), seizures (3/3 - variable age of onset) and/or gingival overgrowth (2/3 - prior to initiation of AEDs). Other findings included behavioral abnormalities, mandibular anomalies, abnormal brain imaging and ophthalmologic or (rarely) audiometric evaluations.

All were born to non-consanguineous couples and additional investigations were performed in some.

Variants were identified by WES or trio WGS, with Sanger confirmation/compatible segregation analyses.

In line with the pLoF variants, mRNA studies in fibroblasts from 2 unrelated affected individuals demonstrated significantly reduced (~80-90%) TBC1C2D mRNA levels compared to controls, restored following cycloheximide treatment. Protein was absent in patient fibroblasts.

TBC-domain containing GTPase activating proteins are known as key regulators of RAB GTPase activity. TBC1D2B was shown to colocalize with RAB5-positive endocytic vesicles. CRISPR/Cas9-mediated ko of TBC1D2B in HeLa cells suggested a role in EGF receptor endocytosis and decreased cell viability of TBC1D2B-deficient HeLa cells upon serum deprivation.

Genes encoding other TBC domain-containg GTPase-activating proteins, e.g. TBC1D7 and TBC1D20, TBC1D24 are associated with recessive neurodevelopmental disorders (with ID and/or seizures) and the pathophysiological defect in TBC1D2B-related disorder (deficit in vesicle trafficking and/or cell survival) is proposed to be similar to that of TBC1D24.

Overall this gene can be considered for inclusion with amber/green rating in the ID panel and green in epilepsy panel.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2750 EXOC2 Konstantinos Varvagiannis gene: EXOC2 was added
gene: EXOC2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: EXOC2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: EXOC2 were set to 32639540
Phenotypes for gene: EXOC2 were set to Global developmental delay; Intellectual disability; Abnormality of the face; Abnormality of brain morphology
Penetrance for gene: EXOC2 were set to Complete
Review for gene: EXOC2 was set to AMBER
Added comment: Van Bergen et al (2020 - PMID: 32639540) report on 3 individuals from 2 families, harboring biallelic EXOC2 mutations.

Clinical presentation included DD, ID (severe in 2 subjects from fam1, borderline intellectual functioning in fam2), dysmorphic features and brain abnormalities. Cerebellar anomalies were common to all with a molar tooth sign observed in one (1/3). Other findings limited to subjects from one family included acquired microcephaly, congenital contractures, spastic quadriplegia (each observed 2/3).

Previous investigations were in all cases non-diagnostic. WES identified biallelic EXOC2 mutations in all affected individuals.

EXOC2 encodes an exocyst subunit. The latter is an octameric complex, component of the membrane transport machinery, required for tethering and fusion of vesicles at the plasma membrane. As discussed ,vesicle transport is important for the development of brain and the function of neurons and glia. Exocyst function is also important for delivery of Arl13b to the primary cilium (biallelic ARL13B mutations cause Joubert syndrome 8) and ciliogenesis.

Affected subjects from a broader consanguineous family (fam1) were homozygous for a truncating variant. Fibroblast studies revealed mRNA levels compatible with NMD (further restored in presence of CHX) as well as reduced protein levels. The female belonging to the second non-consanguineous family was found to harbor 2 missense variants in trans configuration.

An exocytosis defect was demonstrated in fibroblasts from individuals belonging to both families. Ciliogenesis appeared to be normal, however Arl13b localization/recruitment to the cilia was reduced compared with control cells with the defect rescued upon exogenous expression of wt EXOC2.

Mutations in other genes encoding components of the exocyst complex have been previously reported in individuals with relevant phenotypes (e.g. EXOC8 in a boy with features of Joubert s. or EXOC4 in nephrotic syndrome).

The authors discuss on the essential role of EXOC2 based on model organism studies (e.g. impaired neuronal membrane traffic, failure of neuronal polarization and neuromuscular junction expansion seen in Drosophila Sec5 (EXOC2) null mutants).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2750 CEP120 Konstantinos Varvagiannis gene: CEP120 was added
gene: CEP120 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CEP120 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CEP120 were set to 27208211
Phenotypes for gene: CEP120 were set to Joubert syndrome 31 (MIM 617761); Short-rib thoracic dysplasia 13 with or without polydactyly (MIM 616300)
Penetrance for gene: CEP120 were set to Complete
Review for gene: CEP120 was set to GREEN
Added comment: Pathogenic CEP120 variants have been reported in recessive ciliopathies, namely Short-rib thoracic dysplasia 13 with or without polydactyly (MIM 616300) and Joubert syndrome 31 (MIM 617761).

The former is associated with a severe/lethal outcome (4 unrelated infants described by Shaheen et al 2015 - PMID: 25361962, 2 fetuses reported by Roosing et al 2016 - PMID: 27208211).

Roosing et al however, also provided details on 4 unrelated subjects with Joubert syndrome diagnosis. All presented with a neurologic phenotype of hypotonia, DD, cognitive impairment and exhibited a molar tooth sign.

As a result, this gene can be considered for inclusion in the ID panel with green rating (>3 individuals/variants, consistent ciliopathy phenotype).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2744 GLS Zornitza Stark edited their review of gene: GLS: Added comment: Another three individuals from two unrelated families reported with early neonatal refractory seizures, structural brain abnormalities and oedema; significantly increased glutamine levels (PMID: 30575854).; Changed rating: GREEN; Changed publications: 30970188, 30239721, 30575854; Changed phenotypes: Epileptic encephalopathy, early infantile, 71, MIM# 618328, Global developmental delay, progressive ataxia, and elevated glutamine, MIM# 618412
Intellectual disability syndromic and non-syndromic v0.2744 PLCB1 Zornitza Stark Phenotypes for gene: PLCB1 were changed from to Epileptic encephalopathy, early infantile, 12 (MIM#613722)
Intellectual disability syndromic and non-syndromic v0.2737 PLCB1 Crystle Lee reviewed gene: PLCB1: Rating: GREEN; Mode of pathogenicity: None; Publications: 24684524, 20833646, 22690784, 26818157; Phenotypes: Epileptic encephalopathy, early infantile, 12 (MIM#613722); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2722 EXOC7 Chirag Patel gene: EXOC7 was added
gene: EXOC7 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: EXOC7 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: EXOC7 were set to PMID: 32103185
Phenotypes for gene: EXOC7 were set to brain atrophy; seizures; developmental delay; microcephaly
Review for gene: EXOC7 was set to GREEN
Added comment: 4 families with 8 affected individuals with brain atrophy, seizures, and developmental delay, and in more severe cases microcephaly and infantile death. Four novel homozygous or comp.heterozygous variants found in EXOC7, which segregated with disease in the families. They showed that EXOC7, a member of the mammalian exocyst complex, is highly expressed in developing human cortex. In addition, a zebrafish model of Exoc7 deficiency recapitulates the human disorder with increased apoptosis and decreased progenitor cells during telencephalon development, suggesting that the brain atrophy in human cases reflects neuronal degeneration.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2720 HNRNPH1 Chirag Patel gene: HNRNPH1 was added
gene: HNRNPH1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HNRNPH1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: HNRNPH1 were set to PMID: 32335897; 29938792
Phenotypes for gene: HNRNPH1 were set to HNRNPH1 ‐related syndromic intellectual disability
Review for gene: HNRNPH1 was set to GREEN
Added comment: 1st patient reported in 2018 with intellectual disability and dysmorphic features and HNRNPH1 heterozygous missense variant.

2020 paper reports additional 7 cases with ID, short stature, microcephaly, distinctive dysmorphic facial features, and congenital anomalies (cranial, brain, genitourinary, palate, ophthalmologic). They all had HNRNPH1 heterozygous pathogenic variants (missense, frameshift, in‐frame deletion, entire gene duplication) and were identified using clinical networks and GeneMatcher. No comments in paper if all de novo.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2719 PDCD6IP Chirag Patel gene: PDCD6IP was added
gene: PDCD6IP was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PDCD6IP was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PDCD6IP were set to PMID: 32286682
Phenotypes for gene: PDCD6IP were set to Primary microcephaly
Review for gene: PDCD6IP was set to RED
Added comment: One consanguineous family with 2 affected sibs with primary microcephaly (-4SD), intellectual disability and short stature (-5/6SD), and homozygous frameshift variant in PDCD6IP. The homozygous variant was confirmed in both affected sibs, while the four healthy siblings and parents were heterozygous. The clinical features observed in the patients were similar to the phenotypes observed in mouse and zebrafish models of PDCD6IP mutations in previous studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2716 CDK19 Zornitza Stark Phenotypes for gene: CDK19 were changed from Intellectual disability; epileptic encephalopathy to Intellectual disability; epileptic encephalopathy; Epileptic encephalopathy, early infantile, 87, MIM# 618916
Intellectual disability syndromic and non-syndromic v0.2715 CDK19 Zornitza Stark edited their review of gene: CDK19: Changed phenotypes: Intellectual disability, epileptic encephalopathy, Epileptic encephalopathy, early infantile, 87, MIM# 618916
Intellectual disability syndromic and non-syndromic v0.2703 GOLGA2 Elena Savva gene: GOLGA2 was added
gene: GOLGA2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GOLGA2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GOLGA2 were set to PMID: 30237576; 26742501
Phenotypes for gene: GOLGA2 were set to Neuromuscular disorder
Review for gene: GOLGA2 was set to AMBER
Added comment: PMID: 30237576 - One 11 year old patient with a homozygous PTC.
Patient had global dev delay, microcephaly, distal muscle weakness with joint contractures and elevated CK levels. Muscle biopsy showed dystrophin changes. MRI at 2 years old showed brain atrophy with thin corpus callosum and hypomyelination. No seizures or regression.

PMID: 26742501 - One infant with a homozygous PTC.
Patient had dev delay, seizures, microcephaly and muscular dystrophy. Zebrafish null model recapitulates the human phenotype with microcephaly and skeletal muscle disorganization.

Summary: 2 patients
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2698 SCN3A Zornitza Stark Phenotypes for gene: SCN3A were changed from to Epilepsy, familial focal, with variable foci 4, MIM# 617935; Epileptic encephalopathy, early infantile, 62, MIM# 617938; Intellectual disability; Malformations of cortical development
Intellectual disability syndromic and non-syndromic v0.2694 SCN3A Zornitza Stark reviewed gene: SCN3A: Rating: GREEN; Mode of pathogenicity: Other; Publications: 32515017; Phenotypes: Epilepsy, familial focal, with variable foci 4, MIM# 617935, Epileptic encephalopathy, early infantile, 62, MIM# 617938, Intellectual disability, Malformations of cortical development; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2687 PSMB1 Zornitza Stark gene: PSMB1 was added
gene: PSMB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: PSMB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PSMB1 were set to 32129449
Phenotypes for gene: PSMB1 were set to Intellectual disability; microcephaly
Review for gene: PSMB1 was set to AMBER
Added comment: Two siblings reported with a homozygous missense variant in this gene; supportive experimental evidence including zebrafish model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2686 C16orf62 Zornitza Stark changed review comment from: HGNC approved name: VPS35L. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 25434475).
Sources: Expert list; to: HGNC approved name: VPS35L. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 25434475;31712251).
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2683 C16orf62 Zornitza Stark gene: C16orf62 was added
gene: C16orf62 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: C16orf62 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: C16orf62 were set to 25434475
Phenotypes for gene: C16orf62 were set to 3C/Ritscher-Schinzel-like syndrome
Review for gene: C16orf62 was set to AMBER
Added comment: HGNC approved name: VPS35L. Two variants have been reported as compound heterozygotes in two sibs with features of 3C/Ritscher-Schinzel syndrome. Functional studies show that loss of VPS35L function results in impared autophagy and VPS35L knockout mouse resulted in early embrionic lethality (PMID 25434475).
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2677 GRM7 Zornitza Stark gene: GRM7 was added
gene: GRM7 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GRM7 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GRM7 were set to 32286009; 32248644
Phenotypes for gene: GRM7 were set to Epilepsy, microcephaly, developmental delay
Review for gene: GRM7 was set to GREEN
Added comment: Eleven individuals from six families reported, three different homozygous variants (two missense, one LoF). Developmental delay, neonatal‐ or infantile‐onset epilepsy, and microcephaly were universal. Supportive mouse model.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2676 OTUD7A Zornitza Stark Phenotypes for gene: OTUD7A were changed from Epileptic encephalopathy, no OMIM# yet to Epileptic encephalopathy, intellectual disability, no OMIM# yet
Intellectual disability syndromic and non-syndromic v0.2664 OTUD7A Chirag Patel gene: OTUD7A was added
gene: OTUD7A was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: OTUD7A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: OTUD7A were set to PMID: 31997314
Phenotypes for gene: OTUD7A were set to Epileptic encephalopathy, no OMIM# yet
Review for gene: OTUD7A was set to RED
Added comment: One patient with severe global developmental delay, language impairment and epileptic encephalopathy. Homozygous OTUD7A missense variant (c.697C>T, p.Leu233Phe), predicted to alter an ultraconserved amino acid, lying within the OTU catalytic domain. Its subsequent segregation analysis revealed that the parents, presenting with learning disability, and brother were heterozygous carriers. Biochemical assays demonstrated that proteasome complex formation and function were significantly reduced in patient‐derived fibroblasts and in OTUD7A knockout HAP1 cell line. We provide evidence that biallelic pathogenic OTUD7A variation is linked to early‐onset epileptic encephalopathy and proteasome dysfunction. Gene lies in the chromosome 15q13.3 region. Heterozygous microdeletions of chromosome 15q13.3 show incomplete penetrance and are associated with a highly variable phenotype that may include intellectual disability, epilepsy, facial dysmorphism and digit anomalies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2659 TTC5 Konstantinos Varvagiannis gene: TTC5 was added
gene: TTC5 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TTC5 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TTC5 were set to 29302074; 32439809
Phenotypes for gene: TTC5 were set to Central hypotonia; Global developmental delay; Intellectual disability; Abnormality of nervous system morphology; Microcephaly; Abnormality of the face; Behavioral abnormality; Abnormality of the genitourinary system
Penetrance for gene: TTC5 were set to Complete
Review for gene: TTC5 was set to GREEN
Added comment: Hu et al (2019 - PMID: 29302074) reported briefly on 3 individuals from 2 consanguineous families (from Turkey and Iran) with biallelic TTC5 variants. Features included DD (3/3), ID (severe in 2/2 with relevant age), microcephaly (3/3), brain abnormalities, etc. A nonsense and a variant affecting splice site were identified by WES/WGS.

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In a recent report, Rasheed et al (2020 - PMID: 32439809) report on the phenotype of 8 individuals - belonging to 5 consanguineous families - all 8 harboring homozygous TTC5 mutations.

Frequent features included hypotonia (6/8), motor and speech delay, moderate to severe ID (10/10 of relevant age - inclusion of less severely affected subjects was not considered by study design), brain MRI abnormalities (8/8). Other findings included microcephaly in some (6/11), behavioral abnormalities in few (autistic behavior in 2/8, aggression in 2/8), genitourinary anomalies (2/8), seizures (1/11). Facial phenotype incl. thin V-shaped upper lip, low-set ears (in most) and/or additional features.

TTC5 encodes a 440 aa protein, functioning as a scaffold to stabilise p300-JMY interactions. Apart from this role in nucleus, it has functions in the cytoplasm (inhibiting actin nucleataion, autophagosome formation, etc).

The gene has ubiquitous expression, highest in brain.

All variants were identified following WES - as the best candidates - in affected individuals with compatible Sanger studies in all affected family members and carrier parents.

2 missense and 2 nonsense variants were identified with the 2 missense SNVs localizing within TPR domains. qRT-PCR studies for a nonsense variant localizing 19 nt before the last exon, revealed fourfold decreased expression in affected individuals compared to carriers.

Families from Egypt shared a homozygous ~6.3 Mb haplotype block spanning TTC5, suggesting that p.(Arg263Ter) is likely a founder mutation.

The authors underscore some phenotypic (though not facial) similarities with Rubinstein-Taybi syndrome 2 due to EP300 mutations (in line with the role of TTC5).

Biallelic variants in genes encoding other members of the TTC family (containing a TPR motif), e.g. TTC8 or TTC15 cause disorders with neurologic manifestations (and DD/ID).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2657 HIST1H4J Sue White gene: HIST1H4J was added
gene: HIST1H4J was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: HIST1H4J was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: HIST1H4J were set to 31804630
Phenotypes for gene: HIST1H4J were set to microcephaly; intellectual disability; dysmorphic features
Penetrance for gene: HIST1H4J were set to Complete
Review for gene: HIST1H4J was set to AMBER
Added comment: single case report but with functional evidence in zebrafish and phenotypic similarity to other HIST1H4C phenotype
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2629 ADAM22 Zornitza Stark gene: ADAM22 was added
gene: ADAM22 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: ADAM22 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ADAM22 were set to 27066583; 30237576
Phenotypes for gene: ADAM22 were set to Epileptic encephalopathy, early infantile, 61, MIM# 617933
Review for gene: ADAM22 was set to AMBER
Added comment: Two families reported; the second one as part of a large consanguineous cohort.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.2627 UGDH Konstantinos Varvagiannis gene: UGDH was added
gene: UGDH was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: UGDH was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: UGDH were set to 32001716
Phenotypes for gene: UGDH were set to Epileptic encephalopathy, early infantile, 84 - MIM #618792
Penetrance for gene: UGDH were set to Complete
Review for gene: UGDH was set to GREEN
Added comment: Hengel et al (2020 - PMID: 32001716) report on 36 individuals with biallelic UGDH pathogenic variants.

The phenotype corresponded overall to a developmental epileptic encephalopathy with hypotonia, feeding difficulties, severe global DD, moderate or commonly severe ID in all. Hypotonia and motor disorder (incl. spasticity, dystonia, ataxia, chorea, etc) often occurred prior to the onset of seizures. A single individual did not present seizures and 2 sibs had only seizures in the setting of fever.

Affected subjects were tested by exome sequencing and UGDH variants were the only/best candidates for the phenotype following also segregation studies. Many were compound heterozygous or homozygous (~6 families were consanguineous) for missense variants and few were compound heterozygous for missense and pLoF variants. There were no individuals with biallelic pLoF variants identified. Parental/sib studies were all compatible with AR inheritance mode.

UGDH encodes the enzyme UDP-glucose dehydrogenase which converts UDP-glucose to UDP-glucuronate, the latter being a critical component of the glycosaminoglycans, hyaluronan, chondroitin sulfate, and heparan sulfate [OMIM].

Patient fibroblast and biochemical assays suggested a LoF effect of variants leading to impairment of UGDH stability, oligomerization or enzymatic activity (decreased UGDH-catalyzed reduction of NAD+ to NADH / hyaluronic acid production which requires UDP-glucuronate).

Attempts to model the disorder using an already developped zebrafish model (for a hypomorphic LoF allele) were unsuccessful as fish did not exhibit seizures spontaneously or upon induction with PTZ.

Modelling of the disorder in vitro using patient-derived cerebral organoids demonstrated smaller organoids due to reduced number of proliferating neural progenitors.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2625 YIF1B Konstantinos Varvagiannis gene: YIF1B was added
gene: YIF1B was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: YIF1B was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: YIF1B were set to 32006098
Phenotypes for gene: YIF1B were set to Central hypotonia; Failure to thrive; Microcephaly; Global developmental delay; Intellectual disability; Seizures; Spasticity; Abnormality of movement
Penetrance for gene: YIF1B were set to Complete
Review for gene: YIF1B was set to GREEN
Added comment: AlMuhaizea et al (2020 - PMID: 32006098) report on the phenotype of 6 individuals (from 5 families) with biallelic YIF1B truncating variants.

Affected subjects presented hypotonia, failure to thrive, microcephaly (5/6), severe global DD and ID (as evident from best motor/language milestones achieved - Table S1) as well as features suggestive of a motor disorder (dystonia/spasticity/dyskinesia). Seizures were reported in 2 unrelated individuals (2/6). MRI abnormalities were observed in some with thin CC being a feature in 3.

Variable initial investigations were performed including SNP CMA, MECP2, microcephaly / neurotransmitter disorders gene panel testing did not reveal P/LP variants.

YIF1B variants were identified in 3 families within ROH. Following exome sequencing, affected individuals were found to be homozygous for truncating variants (4/5 families being consanguineous). The following 3 variants were identified (NM_001039672.2) : c.186dupT or p.Ala64fs / c.360_361insACAT or p.Gly121fs / c.598G>T or p.Glu200*.

YIF1B encodes an intracellular transmembrane protein.

It has been previously demonstrated that - similarly to other proteins of the Yip family being implicated in intracellular traffic between the Golgi - Yif1B is involved in the anterograde traffic pathway. Yif1B KO mice demonstrate a disorganized Golgi architecture in pyramidal hippocampal neurons (Alterio et al 2015 - PMID: 26077767). The rat ortholog interacts with serotonin receptor 1 (5-HT1AR) with colocalization of Yif1BB and 5-HT1AR in intermediate compartment vesicles and involvement of the former in intracellular trafficing/modulation of 5-HT1AR transport to dendrites (PMID cited: 18685031).

Available mRNA and protein expression data (Protein Atlas) suggest that the gene is widely expressed in all tissues incl. neuronal cells. Immunochemistry data from the Human Brain Atlas also suggest that YIF1B is found in vesicles and localized to the Golgi apparatus. Immunohistochemistry in normal human brain tissue (cerebral cortex) demonstrated labeling of neuronal cells (Human Protein Atlas).

Functional/network analysis of genes co-regulated with YIF1B based on available RNAseq data, suggest enrichement in in genes important for nervous system development and function.

Please consider inclusion in other panels that may be relevant (e.g. microcephaly, etc).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2619 CDC42BPB Konstantinos Varvagiannis gene: CDC42BPB was added
gene: CDC42BPB was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CDC42BPB was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Publications for gene: CDC42BPB were set to 32031333
Phenotypes for gene: CDC42BPB were set to Central hypotonia; Global developmental delay; Intellectual disability; Seizures; Autistic behavior; Behavioral abnormality
Penetrance for gene: CDC42BPB were set to unknown
Review for gene: CDC42BPB was set to GREEN
Added comment: Chilton et al (2020 - PMID: 32031333) report on 14 individuals with missense and loss-of-function CDC42BPB variants.

Features included hypotonia (8/11), DD (12/13 - the 14th was a fetus), ID (7/13), ASD (8/12), clinical seizures (in 3 - a 4th had abnormal EEG without seizures), behavioral abnormalities. Variable non-specific dysmorphic features were reported in some (sparse hair being the most frequent - 4/8). Additional features were observed in few (=<4) incl. cryptorchidism, ophthalmological issues, constipation, kidney abnormalities, micropenis, etc.

All individuals had non-diagnostic prior genetic testing (incl. CMA, FMR1, MECP2, Angelman/Prader-Willi methylation studies, autism gene panel - suggesting relevance to the current panel) or metabolic testing.

Variants were identified following clinical exome sequencing with Sanger confirmation. Most occurred as de novo events (11/14) while inheritance was not available for few (3/14). Missense variants did not display (particular) clustering.

Almost all variants were absent from gnomAD and were predicted to be deleterious in silico (among others almost all had CADD scores >25).

As the authors comment, CDC42BPB encodes myotonic dystrophy-related Cdc42-binding kinase β (MRCKβ) a serine/threonine protein kinase playing a role in regulation of cytoskeletal reorganization and cell migration in nonmuscle cells (through phosporylation of MLC2).

Previous studies have demonstrated that it is ubiquitously expressed with prenatal brain expression.

The gene appears to be intolerant to pLoF (pLI of 1) as well as to missense variants (Z-score of 3.66).

CDC42BPB is a downstream effector of CDC42. Mutations of the latter cause Takenouchi-Kosaki syndrome with DD/ID and some further overlapping features (with CDC42BPB-associated phenotypes).

Homozygous Cdc42bpb KO in mouse appears to be nonviable (MGI:2136459). Loss of gek in the eyes of Drosophila results in disrupted growth cone targeting to the lamina (gek is the fly CDC42BPB ortholog).

Please consider inclusion with amber / green rating in the ID panel (>=4 relevant individuals / variants) and other panels (e.g. for epilepsy, ASD).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2609 EMX2 Zornitza Stark Phenotypes for gene: EMX2 were changed from to Schizencephaly, MIM# 269160
Intellectual disability syndromic and non-syndromic v0.2605 EMX2 Zornitza Stark reviewed gene: EMX2: Rating: AMBER; Mode of pathogenicity: None; Publications: 8528262, 9359037, 9153481, 9153481, 18409201; Phenotypes: Schizencephaly, MIM# 269160; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2605 ATAD3A Zornitza Stark Phenotypes for gene: ATAD3A were changed from Harel-Yoon syndrome, MIM# 617183 to Harel-Yoon syndrome, MIM# 617183; Pontocerebellar hypoplasia, hypotonia, and respiratory insufficiency syndrome, neonatal lethal (PHRINL SYNDROME) 618810
Intellectual disability syndromic and non-syndromic v0.2602 ATAD3A Zornitza Stark edited their review of gene: ATAD3A: Added comment: Note mode of pathogenicity includes:
i) bi-allelic missense and nonsense variants and bi-allelic deletions that create an ATAD3B/ATAD3A fusion gene under the lowly expressed ATAD3B promoter
ii) monoallelic dominant-negative missense variants (either de novo or inherited) and de novo monoallelic duplications creating a dominant negative ATAD3A/ATAD3C fusion gene; Changed publications: 27640307, 32004445, 28549128; Changed phenotypes: Harel-Yoon syndrome, MIM# 617183, Pontocerebellar hypoplasia, hypotonia, and respiratory insufficiency syndrome, neonatal lethal (PHRINL SYNDROME) 618810
Intellectual disability syndromic and non-syndromic v0.2602 MN1 Zornitza Stark Phenotypes for gene: MN1 were changed from Intellectual disability; dysmophic features; rhombencephalosynapsis to CEBALID syndrome, MIM#618774; Intellectual disability; dysmophic features; rhombencephalosynapsis
Intellectual disability syndromic and non-syndromic v0.2599 VPS51 Zornitza Stark gene: VPS51 was added
gene: VPS51 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: VPS51 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: VPS51 were set to 30624672; 31207318
Phenotypes for gene: VPS51 were set to Pontocerebellar hypoplasia, type 13, MIM# 618606
Review for gene: VPS51 was set to AMBER
Added comment: Two families reported with bi-allelic variants in this gene and global developmental delay, impaired intellectual development with absent speech, microcephaly, and progressive atrophy of the cerebellar vermis and brainstem. Additional features, including seizures and visual impairment, are variable.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2597 CDK19 Zornitza Stark gene: CDK19 was added
gene: CDK19 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CDK19 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CDK19 were set to 32330417
Phenotypes for gene: CDK19 were set to Intellectual disability; epileptic encephalopathy
Review for gene: CDK19 was set to GREEN
Added comment: Three unrelated individuals with de novo missense variants reported, and intellectual disability/epileptic encephalopathy. Supportive functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2594 PTPN23 Zornitza Stark Phenotypes for gene: PTPN23 were changed from to Intellectual disability; brain abnormalities; seizures; optic atrophy; microcephaly
Intellectual disability syndromic and non-syndromic v0.2593 PTPN23 Zornitza Stark reviewed gene: PTPN23: Rating: GREEN; Mode of pathogenicity: None; Publications: 31395947; Phenotypes: Intellectual disability, brain abnormalities, seizures, optic atrophy, microcephaly; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2592 CYFIP2 Zornitza Stark Phenotypes for gene: CYFIP2 were changed from Epileptic encephalopathy, early infantile, 65, MIM#618008 to Epileptic encephalopathy, early infantile, 65, MIM#618008; Intellectual disability
Intellectual disability syndromic and non-syndromic v0.2590 CYFIP2 Zornitza Stark edited their review of gene: CYFIP2: Added comment: Further 12 independent patients with a variety of de novo variants in CYFIP2 reported with eight distinct de novo variants and a shared phenotype of intellectual disability, seizures, and muscular hypotonia. Seven different missense variants detected, of which two occurred recurrently (p.(Arg87Cys) and p.(Ile664Met)). Preliminary genotype–phenotype correlation indicates a profound phenotype in p.Arg87 substitutions and a more variable phenotype in other alterations.; Changed publications: 29534297, 30664714; Changed phenotypes: Epileptic encephalopathy, early infantile, 65, MIM#618008, Intellectual disability
Intellectual disability syndromic and non-syndromic v0.2589 CEP55 Zornitza Stark gene: CEP55 was added
gene: CEP55 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CEP55 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CEP55 were set to 32100459
Phenotypes for gene: CEP55 were set to Multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia, and hydranencephaly, MIM# 236500; Microcephaly; Intellectual disability
Review for gene: CEP55 was set to GREEN
Added comment: Homozygous nonsense variants in CEP55 are associated with a lethal condition characterized by multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia, and hydranencephaly (MARCH syndrome) also known as Meckel-like syndrome. New report of seven living individuals from five families with biallelic CEP55 variants. Four unrelated individuals with microcephaly, speech delays, and bilateral toe syndactyly all had a common CEP55 variant c.70G>A p.(Glu24Lys) in trans with nonsense variants. Three siblings were homozygous for a consensus splice site variant near the end of the gene. These affected girls all had severely delayed development, microcephaly, and varying degrees of lissencephaly/pachygyria. This series suggests that individuals with compound heterozygosity for nonsense and missense variants in CEP55 have a different viable phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2582 KCNB1 Zornitza Stark Phenotypes for gene: KCNB1 were changed from to Epileptic encephalopathy, early infantile, 26, MIM# 616056
Intellectual disability syndromic and non-syndromic v0.2579 KCNB1 Zornitza Stark reviewed gene: KCNB1: Rating: GREEN; Mode of pathogenicity: None; Publications: 31600826, 31513310; Phenotypes: Epileptic encephalopathy, early infantile, 26, MIM# 616056; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2577 GAD1 Zornitza Stark Phenotypes for gene: GAD1 were changed from Cerebral palsy, spastic quadriplegic, 1, MIM#603513 to Cerebral palsy, spastic quadriplegic, 1, MIM#603513; Developmental and epileptic encephalopathy
Intellectual disability syndromic and non-syndromic v0.2575 GAD1 Zornitza Stark edited their review of gene: GAD1: Added comment: 2020: 11 individuals from 6 consanguineous families reported with bi-allelic LOF variant and a developmental/epileptic encephalopathy. Seizure onset occurred in the first 2 months of life in all. All 10 individuals, from whom early disease history was available, presented with seizure onset in the first month of life, mainly consisting of epileptic spasms or myoclonic seizures. Early EEG showed suppression-burst or pattern of burst attenuation or hypsarrhythmia if only recorded in the post-neonatal period. Eight individuals had joint contractures and/or pes equinovarus. Seven presented a cleft palate and two also had an omphalocele, reproducing the phenotype of the knockout Gad1−/− mouse model. Four individuals died before 4 years of age.; Changed publications: 15571623, 32282878; Changed phenotypes: Cerebral palsy, spastic quadriplegic, 1, MIM#603513, Developmental and epileptic encephalopathy
Intellectual disability syndromic and non-syndromic v0.2552 GABRA1 Zornitza Stark Phenotypes for gene: GABRA1 were changed from to Epileptic encephalopathy, early infantile, 19 615744; Rett syndrome; Rett-like phenotypes; idiopathic generalized Epilepsy; Dravet syndrome
Intellectual disability syndromic and non-syndromic v0.2549 GABRA1 Zornitza Stark reviewed gene: GABRA1: Rating: GREEN; Mode of pathogenicity: None; Publications: 11992121, 21714819, 24623842, 30842224; Phenotypes: Epileptic encephalopathy, early infantile, 19 615744, Rett syndrome, Rett-like phenotypes, idiopathic generalized Epilepsy, Dravet syndrome; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2543 GSX2 Zornitza Stark gene: GSX2 was added
gene: GSX2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GSX2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GSX2 were set to 31412107
Phenotypes for gene: GSX2 were set to Diencephalic-mesencephalic junction dysplasia syndrome 2 618646; Intellectual disability; Dystonia; Spastic tetra paresis
Review for gene: GSX2 was set to AMBER
Added comment: Two unrelated families, some functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2521 NUP188 Zornitza Stark Phenotypes for gene: NUP188 were changed from microcephaly; ID; cataract to microcephaly; ID; cataract; structural brain abnormalities; hypoventilation
Intellectual disability syndromic and non-syndromic v0.2518 NUP188 Zornitza Stark edited their review of gene: NUP188: Added comment: Additional 6 unrelated individuals reported, promoted to Green.; Changed rating: GREEN; Changed publications: 32021605, 28726809, 32275884; Changed phenotypes: microcephaly, ID, cataract, structural brain abnormalities, hypoventilation
Intellectual disability syndromic and non-syndromic v0.2518 AP3B2 Zornitza Stark Phenotypes for gene: AP3B2 were changed from to Early-onset epileptic encephalopathy with optic atrophy, MIM#617276
Intellectual disability syndromic and non-syndromic v0.2515 AP3B2 Zornitza Stark reviewed gene: AP3B2: Rating: GREEN; Mode of pathogenicity: None; Publications: 27889060; Phenotypes: Early-onset epileptic encephalopathy with optic atrophy, MIM#617276; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2506 FRMD4A Zornitza Stark Phenotypes for gene: FRMD4A were changed from Intellectual disability; microcephaly to Intellectual disability; microcephaly; Corpus callosum, agenesis of, with facial anomalies and cerebellar ataxia, MIM# 616819
Intellectual disability syndromic and non-syndromic v0.2504 FRMD4A Zornitza Stark edited their review of gene: FRMD4A: Changed phenotypes: Intellectual disability, microcephaly, Corpus callosum, agenesis of, with facial anomalies and cerebellar ataxia, MIM# 616819
Intellectual disability syndromic and non-syndromic v0.2504 FRMD4A Zornitza Stark edited their review of gene: FRMD4A: Changed phenotypes: Intellectual disability, microcephaly, Corpus callosum, agenesis of, with facial anomalies and cerebellar ataxia 616819
Intellectual disability syndromic and non-syndromic v0.2504 FRMD4A Zornitza Stark gene: FRMD4A was added
gene: FRMD4A was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: FRMD4A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FRMD4A were set to 25388005; 30214071
Phenotypes for gene: FRMD4A were set to Intellectual disability; microcephaly
Review for gene: FRMD4A was set to AMBER
Added comment: Single Bedouin Israeli family reported with homozygous variant initially. Good segregation data. No functional data. Another family reported as part of a large consanguineous microcephaly cohort, different variant.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.2499 ADARB1 Zornitza Stark gene: ADARB1 was added
gene: ADARB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: ADARB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ADARB1 were set to 32220291
Phenotypes for gene: ADARB1 were set to Intellectual disability; microcephaly; seizures
Review for gene: ADARB1 was set to GREEN
Added comment: Four unrelated individuals with bi-allelic variants in this gene.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2490 ADGRG6 Zornitza Stark reviewed gene: ADGRG6: Rating: RED; Mode of pathogenicity: None; Publications: 30549416, 26004201; Phenotypes: Lethal congenital contracture syndrome 9, OMIM #616503; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2476 QARS Zornitza Stark Phenotypes for gene: QARS were changed from to Microcephaly, progressive, seizures, and cerebral and cerebellar atrophy, MIM# 615760
Intellectual disability syndromic and non-syndromic v0.2473 QARS Zornitza Stark reviewed gene: QARS: Rating: GREEN; Mode of pathogenicity: None; Publications: 28620870, 25471517, 25432320, 25041233, 24656866, 32042906; Phenotypes: Microcephaly, progressive, seizures, and cerebral and cerebellar atrophy, MIM# 615760; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2469 ISCA1 Zornitza Stark gene: ISCA1 was added
gene: ISCA1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: ISCA1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ISCA1 were set to 28356563; 32092383; 31016283; 30113620; 30105122
Phenotypes for gene: ISCA1 were set to Multiple mitochondrial dysfunctions syndrome 5, MIM# 617613
Review for gene: ISCA1 was set to GREEN
gene: ISCA1 was marked as current diagnostic
Added comment: Multiple unrelated families reported. Severe disorder characterised by progressive neurologic deterioration beginning in early infancy. Affected individuals have essentially no psychomotor development and have early-onset seizures with neurologic decline and spasticity. Brain imaging shows severe leukodystrophy with evidence of dys- or delayed myelination. Rat model results in early lethality. Founder variant c.259G > A, p.(Glu87Lys) reported in Indian families.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2453 RPS23 Zornitza Stark Phenotypes for gene: RPS23 were changed from Brachycephaly, trichomegaly, and developmental delay, MIM# 617412 to Brachycephaly, trichomegaly, and developmental delay, MIM# 617412
Intellectual disability syndromic and non-syndromic v0.2453 RPS23 Zornitza Stark Phenotypes for gene: RPS23 were changed from to Brachycephaly, trichomegaly, and developmental delay, MIM# 617412
Intellectual disability syndromic and non-syndromic v0.2449 RPS23 Zornitza Stark reviewed gene: RPS23: Rating: AMBER; Mode of pathogenicity: None; Publications: 28257692; Phenotypes: Brachycephaly, trichomegaly, and developmental delay, MIM# 617412; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2448 RNF13 Zornitza Stark gene: RNF13 was added
gene: RNF13 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: RNF13 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RNF13 were set to 30595371
Phenotypes for gene: RNF13 were set to Epileptic encephalopathy, early infantile, 73 618379
Mode of pathogenicity for gene: RNF13 was set to Other
Review for gene: RNF13 was set to GREEN
Added comment: Three unrelated individuals with de novo variants in this gene and severe neurological phenotype, including microcephaly, seizures, visual impairment, profound developmental delay.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2443 RHEB Zornitza Stark Phenotypes for gene: RHEB were changed from to Intellectual disability; Macrocephaly; Focal cortical dysplasia
Intellectual disability syndromic and non-syndromic v0.2440 RHEB Zornitza Stark reviewed gene: RHEB: Rating: GREEN; Mode of pathogenicity: None; Publications: 31337748, 29051493; Phenotypes: Intellectual disability, Macrocephaly, Focal cortical dysplasia; Mode of inheritance: Other
Intellectual disability syndromic and non-syndromic v0.2439 MRPS34 Zornitza Stark gene: MRPS34 was added
gene: MRPS34 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: MRPS34 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MRPS34 were set to 28777931
Phenotypes for gene: MRPS34 were set to Combined oxidative phosphorylation deficiency 32, MIM# 617664
Review for gene: MRPS34 was set to GREEN
gene: MRPS34 was marked as current diagnostic
Added comment: Six individuals from 4 unrelated families; clinical presentation is with developmental delay/regression. More variable features include movement disorders, microcephaly, strabismus, nystagmus, optic atrophy.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2437 MFSD2A Zornitza Stark gene: MFSD2A was added
gene: MFSD2A was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: MFSD2A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MFSD2A were set to 26005865; 26005868; 24828044
Phenotypes for gene: MFSD2A were set to Microcephaly 15, primary, autosomal recessive, MIM# 616486
Review for gene: MFSD2A was set to GREEN
Added comment: Three unrelated families and two animal models.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2420 TRIO Zornitza Stark changed review comment from: The nonsense mutations are spread along the TRIO sequence, and affected individuals show variable neurodevelopmental phenotypes. In contrast, missense variants cluster into two mutational hotspots in the TRIO sequence, one in the seventh spectrin repeat and one in the RAC1-activating GEFD1.; to: The nonsense mutations are spread along the TRIO sequence, and affected individuals show variable neurodevelopmental phenotypes. In contrast, missense variants cluster into two mutational hotspots in the TRIO sequence, one in the seventh spectrin repeat and one in the RAC1-activating GEFD1. Individuals with a pathogenic variant in the seventh spectrin repeat have a more severe ID associated with macrocephaly than do most individuals with GEFD1 variants, who display milder ID and microcephaly.
Intellectual disability syndromic and non-syndromic v0.2405 NHEJ1 Zornitza Stark Phenotypes for gene: NHEJ1 were changed from to Severe combined immunodeficiency with microcephaly, growth retardation, and sensitivity to ionizing radiation, MIM#611291
Intellectual disability syndromic and non-syndromic v0.2401 NHEJ1 Zornitza Stark reviewed gene: NHEJ1: Rating: RED; Mode of pathogenicity: None; Publications: 16439204; Phenotypes: Severe combined immunodeficiency with microcephaly, growth retardation, and sensitivity to ionizing radiation, MIM#611291; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2397 NDUFV2 Zornitza Stark changed review comment from: Multiple unrelated families.; to: Multiple unrelated families. Common presenting features include HOCM and encephalopathy, unclear in what proportion ID is likely to be the presenting or main feature.
Intellectual disability syndromic and non-syndromic v0.2358 WDR81 Zornitza Stark Phenotypes for gene: WDR81 were changed from to Cerebellar ataxia, mental retardation, and dysequilibrium syndrome 2, 610185; Hydrocephalus, congenital, 3, with brain anomalies, 617967
Intellectual disability syndromic and non-syndromic v0.2349 TUBGCP4 Zornitza Stark gene: TUBGCP4 was added
gene: TUBGCP4 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: TUBGCP4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TUBGCP4 were set to 25817018
Phenotypes for gene: TUBGCP4 were set to Microcephaly and chorioretinopathy, autosomal recessive, 3, 616335
Review for gene: TUBGCP4 was set to AMBER
Added comment: Three unrelated families reported; ID described as mild.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2332 TRAK1 Zornitza Stark Phenotypes for gene: TRAK1 were changed from to Epileptic encephalopathy, early infantile, 68, MIM# 618201
Intellectual disability syndromic and non-syndromic v0.2329 TRAK1 Zornitza Stark reviewed gene: TRAK1: Rating: GREEN; Mode of pathogenicity: None; Publications: 28940097, 28364549, 29846532; Phenotypes: Epileptic encephalopathy, early infantile, 68, MIM# 618201; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2327 TPK1 Zornitza Stark Phenotypes for gene: TPK1 were changed from to Thiamine metabolism dysfunction syndrome 5 (episodic encephalopathy type), MIM# 614458
Intellectual disability syndromic and non-syndromic v0.2324 TPK1 Zornitza Stark reviewed gene: TPK1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Thiamine metabolism dysfunction syndrome 5 (episodic encephalopathy type), MIM# 614458; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2319 SPOP Zornitza Stark gene: SPOP was added
gene: SPOP was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: SPOP was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: SPOP were set to 32109420
Phenotypes for gene: SPOP were set to Intellectual disability; dysmorphism; microcephaly; macrocephaly
Mode of pathogenicity for gene: SPOP was set to Other
Review for gene: SPOP was set to GREEN
Added comment: Seven individuals reported with de novo missense variants in this gene. Gain-of-function variants associated with microcephaly whereas dominant-negative variants associated with macrocephaly.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.2292 TGFB1 Zornitza Stark gene: TGFB1 was added
gene: TGFB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: TGFB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TGFB1 were set to 29483653
Phenotypes for gene: TGFB1 were set to Inflammatory bowel disease, immunodeficiency, and encephalopathy, MIM# 618213
Review for gene: TGFB1 was set to AMBER
Added comment: Three individuals from two unrelated families reported. DD/ID and seizures in addition to IBD/immunodeficiency.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2285 TBC1D7 Zornitza Stark Phenotypes for gene: TBC1D7 were changed from to Macrocephaly/megalencephaly syndrome, autosomal recessive, MIM# 248000
Intellectual disability syndromic and non-syndromic v0.2281 TBC1D7 Zornitza Stark reviewed gene: TBC1D7: Rating: AMBER; Mode of pathogenicity: None; Publications: 24515783, 23687350; Phenotypes: Macrocephaly/megalencephaly syndrome, autosomal recessive, MIM# 248000; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2261 STRADA Zornitza Stark gene: STRADA was added
gene: STRADA was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: STRADA was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: STRADA were set to 17522105; 27170158; 28688840
Phenotypes for gene: STRADA were set to Polyhydramnios, megalencephaly, and symptomatic epilepsy, MIM# 611087
Review for gene: STRADA was set to GREEN
Added comment: Seven distantly related Menonite children plus four other unrelated families reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2250 CEP135 Zornitza Stark Phenotypes for gene: CEP135 were changed from Microcephalic primordial dwarfism; Microcephaly 8, primary, autosomal recessive, 614673 to Microcephalic primordial dwarfism; Microcephaly 8, primary, autosomal recessive, 614673
Intellectual disability syndromic and non-syndromic v0.2250 CEP135 Zornitza Stark Phenotypes for gene: CEP135 were changed from to Microcephalic primordial dwarfism; Microcephaly 8, primary, autosomal recessive, 614673
Intellectual disability syndromic and non-syndromic v0.2247 CEP135 Zornitza Stark reviewed gene: CEP135: Rating: GREEN; Mode of pathogenicity: None; Publications: 30214071, 22521416; Phenotypes: Microcephalic primordial dwarfism, Microcephaly 8, primary, autosomal recessive, 614673; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2237 RAX Sebastian Lunke gene: RAX was added
gene: RAX was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: RAX was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: RAX were set to 30762128; 24033328
Phenotypes for gene: RAX were set to MICROPHTHALMIA, ISOLATED 3; MCOP3
Review for gene: RAX was set to RED
Added comment: Only three cases described with intellectual disability in addition to microphthalmia, no new descriptions of ID association since 2014. Not clear if the cases are from the same or different families. Link with ID seems tenuous at best.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.2230 SNORD118 Zornitza Stark reviewed gene: SNORD118: Rating: AMBER; Mode of pathogenicity: None; Publications: 27571260; Phenotypes: Leukoencephalopathy, brain calcifications, and cysts, MIM# 614561; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2219 WDR81 Zornitza Stark reviewed gene: WDR81: Rating: GREEN; Mode of pathogenicity: None; Publications: 21885617, 28556411, 28969387; Phenotypes: Cerebellar ataxia, mental retardation, and dysequilibrium syndrome 2, 610185, Hydrocephalus, congenital, 3, with brain anomalies, 617967; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2209 PNKP Zornitza Stark Phenotypes for gene: PNKP were changed from to Microcephaly, seizures, and developmental delay, MIM#613402
Intellectual disability syndromic and non-syndromic v0.2206 PNKP Zornitza Stark reviewed gene: PNKP: Rating: GREEN; Mode of pathogenicity: None; Publications: 23224214, 20118933; Phenotypes: Microcephaly, seizures, and developmental delay, MIM#613402; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2202 SLC25A19 Zornitza Stark changed review comment from: Bi-alllelic variants in this gene have been associated with a spectrum of phenotypes, ranging from a severe neonatal disorder in the Amish, with ID as part of the phenotype through to a neuropathy.; to: Bi-alllelic variants in this gene have been associated with a spectrum of phenotypes, ranging from a severe neonatal disorder in the Amish, with ID as part of the phenotype (founder effect) through to a neuropathy/disorder of episodic encephalopathy.
Intellectual disability syndromic and non-syndromic v0.2201 SLC1A2 Zornitza Stark gene: SLC1A2 was added
gene: SLC1A2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: SLC1A2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: SLC1A2 were set to 27476654; 28777935
Phenotypes for gene: SLC1A2 were set to Epileptic encephalopathy, early infantile, 41, MIM#617105; Intellectual disability
Review for gene: SLC1A2 was set to GREEN
gene: SLC1A2 was marked as current diagnostic
Added comment: Four unrelated individuals reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2196 CHD2 Zornitza Stark Phenotypes for gene: CHD2 were changed from to Epileptic encephalopathy, childhood-onset (MIM # 615369)
Intellectual disability syndromic and non-syndromic v0.2151 RPIA Sebastian Lunke gene: RPIA was added
gene: RPIA was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: RPIA was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: RPIA were set to 14988808; 10589548; 20499043; 28801340; 30088433
Phenotypes for gene: RPIA were set to Ribose 5-phosphate isomerase deficiency, MIM 608611
Review for gene: RPIA was set to GREEN
gene: RPIA was marked as current diagnostic
Added comment: From GEL: Three patients described in total, one of these with functional data:

Patient 1 with comp het missense and frameshift as well as functional data, early developmental delay, leukoencephalopathy, seizures with onset at 4 years, with subsequent neurologic regression and peripheral neuropathy

Patient 2 with missense, delayed early development, seizures and regression at the age of 7 with MRI white matter abnormalities

Patient 3 with comp het missense and canonical splice, clinical biochem corroboration ribitol and arabitol in urine demonstrated significant elevations (>20x), neonatal onset leukoencephalopathy and developmental delay
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.2149 PLEKHG2 Zornitza Stark gene: PLEKHG2 was added
gene: PLEKHG2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: PLEKHG2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PLEKHG2 were set to 26539891; 24001768; 26573021
Phenotypes for gene: PLEKHG2 were set to Leukodystrophy and acquired microcephaly with or without dystonia, 616763
Review for gene: PLEKHG2 was set to AMBER
Added comment: Three families reported; however, two had the same homozygous variant (founder effect).
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2144 MECP2 Zornitza Stark Phenotypes for gene: MECP2 were changed from to Encephalopathy, neonatal severe 300673 XLR; Mental retardation, X-linked, syndromic 13 300055 XLR; Rett syndrome 312750 XLD
Intellectual disability syndromic and non-syndromic v0.2139 VARS Chirag Patel gene: VARS was added
gene: VARS was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: VARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: VARS were set to PubMed: 30755616, 30755602, 26539891, 29691655, 30275004
Phenotypes for gene: VARS were set to Neurodevelopmental disorder with microcephaly, seizures, and cortical atrophy; OMIM #617802
Review for gene: VARS was set to GREEN
Added comment: 14 families with 20 affected individuals
- homozygous missense or compound heterozygous mutations in VARS
- mutations segregated with the disorder in the families
- functional studies in some cases
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2138 WDR4 Chirag Patel changed review comment from: Galloway-Mowat syndrome 6, OMIM #618347:

1 family with 2 sibs with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 1 child with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 4 sibs with GMS and homozygous splice site mutation in the WDR4 gene. Functional studies of the variant and studies of patient cells were not performed.



Microcephaly, growth deficiency, seizures, and brain malformations; OMIM #618346:

2 unrelated patients with intrauterine growth retardation, postnatal growth deficiency with severe microcephaly, and poor or absent psychomotor development. Testing found the same homozygous missense mutation in the WDR4 gene, which segregated with the disorder in both families. Studies of patient cells and modeling of the corresponding mutation in yeast showed that the mutation caused a significant reduction in m(7)G46 methylation of specific tRNAs species, particularly at higher temperatures. This was associated with a growth defect in yeast, thus offering a potential mechanism for the growth defects observed in patients with the mutation. The findings suggested that abnormal tRNA modification is a major contributor to disease pathogenesis.
Sources: Expert list; to: Galloway-Mowat syndrome 6, OMIM #618347:

1 family with 2 sibs with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 1 child with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 4 sibs with GMS and homozygous splice site mutation in the WDR4 gene. Functional studies of the variant and studies of patient cells were not performed.
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Microcephaly, growth deficiency, seizures, and brain malformations; OMIM #618346:

2 unrelated patients with intrauterine growth retardation, postnatal growth deficiency with severe microcephaly, and poor or absent psychomotor development. Testing found the same homozygous missense mutation in the WDR4 gene, which segregated with the disorder in both families. Studies of patient cells and modeling of the corresponding mutation in yeast showed that the mutation caused a significant reduction in m(7)G46 methylation of specific tRNAs species, particularly at higher temperatures. This was associated with a growth defect in yeast, thus offering a potential mechanism for the growth defects observed in patients with the mutation. The findings suggested that abnormal tRNA modification is a major contributor to disease pathogenesis.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2137 WDR4 Chirag Patel gene: WDR4 was added
gene: WDR4 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: WDR4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: WDR4 were set to PubMed: 26416026, 30079490, 29597095, 28617965
Phenotypes for gene: WDR4 were set to Galloway-Mowat syndrome 6, OMIM #618347; Microcephaly, growth deficiency, seizures, and brain malformations, OMIM #618346
Review for gene: WDR4 was set to GREEN
Added comment: Galloway-Mowat syndrome 6, OMIM #618347:

1 family with 2 sibs with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 1 child with GMS and compound heterozygous mutations in the WDR4 gene, segregated with the disorder in the family. Functional studies of the variants and studies of patient cells were not performed.

1 family with 4 sibs with GMS and homozygous splice site mutation in the WDR4 gene. Functional studies of the variant and studies of patient cells were not performed.



Microcephaly, growth deficiency, seizures, and brain malformations; OMIM #618346:

2 unrelated patients with intrauterine growth retardation, postnatal growth deficiency with severe microcephaly, and poor or absent psychomotor development. Testing found the same homozygous missense mutation in the WDR4 gene, which segregated with the disorder in both families. Studies of patient cells and modeling of the corresponding mutation in yeast showed that the mutation caused a significant reduction in m(7)G46 methylation of specific tRNAs species, particularly at higher temperatures. This was associated with a growth defect in yeast, thus offering a potential mechanism for the growth defects observed in patients with the mutation. The findings suggested that abnormal tRNA modification is a major contributor to disease pathogenesis.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2132 MECP2 Michelle Torres reviewed gene: MECP2: Rating: GREEN; Mode of pathogenicity: None; Publications: 20301670; Phenotypes: Encephalopathy, neonatal severe 300673 XLR, Mental retardation, X-linked syndromic, Lubs type 300260 XLR, Mental retardation, X-linked, syndromic 13 300055 XLR, Rett syndrome 312750 XLD, Rett syndrome, atypical 312750 XLD, Rett syndrome, preserved speech variant 312750 XLD, {Autism susceptibility, X-linked 3} 300496 XL; Mode of inheritance: Other; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.2130 UFC1 Chirag Patel gene: UFC1 was added
gene: UFC1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: UFC1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: UFC1 were set to PubMed: 29868776
Phenotypes for gene: UFC1 were set to Neurodevelopmental disorder with spasticity and poor growth; OMIM #618076
Review for gene: UFC1 was set to GREEN
Added comment: 3 consanguineous Saudi families with neurodevelopmental disorder with spasticity and poor growth with a homozygous missense mutation in the UFC1 gene. An unrelated Swiss boy with same phenotype found to have a different homozygous mutation in the UFC1 gene. Total 8 patients from 4 families.

The mutations segregated with the disorder in the families. In vitro functional expression studies showed that both mutations caused impaired thioester binding with UFM1 (610553). Patient cells also showed decreased UFC1 intermediate formation with UFM1. The decrease in function was consistent with a hypomorphic allele, and Nahorski et al. (2018) suggested that complete loss of function would be embryonic lethal.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2125 PIGP Zornitza Stark gene: PIGP was added
gene: PIGP was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: PIGP was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PIGP were set to 28334793; 31139695
Phenotypes for gene: PIGP were set to Epileptic encephalopathy, early infantile, 55, 617599
Review for gene: PIGP was set to AMBER
Added comment: Two unrelated families reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2115 ZNF148 Chirag Patel gene: ZNF148 was added
gene: ZNF148 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: ZNF148 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ZNF148 were set to PMID: 27964749
Phenotypes for gene: ZNF148 were set to Global developmental delay, absent or hypoplastic corpus callosum, and dysmorphic facies; OMIM #617260
Review for gene: ZNF148 was set to GREEN
Added comment: 4 patients with de novo heterozygous nonsense or frameshift mutations in the ZNF148 gene. Patients characterized by underdevelopment of the corpus callosum, mild to moderate developmental delay and ID, variable microcephaly or mild macrocephaly, short stature, feeding problems, facial dysmorphisms, and cardiac and renal malformations. No functional evidence.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2101 PHACTR1 Zornitza Stark Phenotypes for gene: PHACTR1 were changed from Seizures:Epileptic encephalopathy, early infantile, 70, MIM# 618298; PHACTR1-associated neurodevelopment disorder to Epileptic encephalopathy, early infantile, 70, MIM# 618298; PHACTR1-associated neurodevelopment disorder
Intellectual disability syndromic and non-syndromic v0.2099 PHACTR1 Zornitza Stark gene: PHACTR1 was added
gene: PHACTR1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: PHACTR1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PHACTR1 were set to 30256902; 28135719; 23033978; 27457812
Phenotypes for gene: PHACTR1 were set to Seizures:Epileptic encephalopathy, early infantile, 70, MIM# 618298; PHACTR1-associated neurodevelopment disorder
Penetrance for gene: PHACTR1 were set to Incomplete
Mode of pathogenicity for gene: PHACTR1 was set to Other
Review for gene: PHACTR1 was set to GREEN
gene: PHACTR1 was marked as current diagnostic
Added comment: 6 unrelated individuals reported altogether with variants in this gene. Several as part of large cohorts, so limited variant and patient characterisation. One variant reported by de Ligt et al is present in the population (4 individuals) suggesting reduced penetrance. However, functional data (including mouse model) for this and other variants exerting a dominant negative effect.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2070 LIPT2 Zornitza Stark gene: LIPT2 was added
gene: LIPT2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: LIPT2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: LIPT2 were set to 28757203
Phenotypes for gene: LIPT2 were set to Encephalopathy, neonatal severe, with lactic acidosis and brain abnormalities, MIM#617668
Review for gene: LIPT2 was set to AMBER
Added comment: Three individuals from two unrelated families; profound ID.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2061 KCNT2 Zornitza Stark gene: KCNT2 was added
gene: KCNT2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: KCNT2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: KCNT2 were set to 29069600; 29740868
Phenotypes for gene: KCNT2 were set to Epileptic encephalopathy, early infantile 57, 617771
Mode of pathogenicity for gene: KCNT2 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: KCNT2 was set to GREEN
gene: KCNT2 was marked as current diagnostic
Added comment: Three unrelated individuals reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2043 INSR Zornitza Stark Phenotypes for gene: INSR were changed from to Leprechaunism, MIM# 246200; Rabson-Mendenhall syndrome, MIM# 262190
Intellectual disability syndromic and non-syndromic v0.2040 INSR Zornitza Stark reviewed gene: INSR: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leprechaunism, MIM# 246200, Rabson-Mendenhall syndrome, MIM# 262190; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.2033 HIST1H4C Zornitza Stark Phenotypes for gene: HIST1H4C were changed from Growth delay, microcephaly and intellectual disability to Growth delay, microcephaly and intellectual disability
Intellectual disability syndromic and non-syndromic v0.2032 HIST1H4C Zornitza Stark Phenotypes for gene: HIST1H4C were changed from to Growth delay, microcephaly and intellectual disability
Intellectual disability syndromic and non-syndromic v0.2029 HIST1H4C Zornitza Stark reviewed gene: HIST1H4C: Rating: AMBER; Mode of pathogenicity: None; Publications: 28920961; Phenotypes: Growth delay, microcephaly and intellectual disability; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.2013 KIF11 Zornitza Stark Phenotypes for gene: KIF11 were changed from to Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation MIM#152950
Intellectual disability syndromic and non-syndromic v0.2007 GRIN2D Zornitza Stark gene: GRIN2D was added
gene: GRIN2D was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: GRIN2D was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: GRIN2D were set to 27616483; 30280376
Phenotypes for gene: GRIN2D were set to Epileptic encephalopathy, early infantile, 46, MIM# 617162; intellectual disability
Mode of pathogenicity for gene: GRIN2D was set to Other
Review for gene: GRIN2D was set to GREEN
gene: GRIN2D was marked as current diagnostic
Added comment: Five unrelated individuals reported, two with recurrent variant (NM_000836.2:c.1999G>A or p.Val667Ile). GoF postulated as mechanism.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.2006 KIF11 Ee Ming Wong reviewed gene: KIF11: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 27212378, 24281367; Phenotypes: 1. Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation (OMIM), 2. Familial exudative vitreoretinopathy (FEVR) (PMID: 27212378); Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1989 TRAPPC4 Zornitza Stark gene: TRAPPC4 was added
gene: TRAPPC4 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert Review
Mode of inheritance for gene: TRAPPC4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TRAPPC4 were set to 31794024
Phenotypes for gene: TRAPPC4 were set to intellectual disability; epilepsy; spasticity; microcephaly
Review for gene: TRAPPC4 was set to GREEN
Added comment: Seven individuals from three unrelated families reported; recurrent splice site variant (hg19:chr11:g.118890966A>G; TRAPPC4: NM_016146.5; c.454+3A>G), not a founder variant.
Sources: Expert Review
Intellectual disability syndromic and non-syndromic v0.1977 GEMIN4 Zornitza Stark Phenotypes for gene: GEMIN4 were changed from to Neurodevelopmental disorder with microcephaly, cataracts, and renal abnormalities, MIM# 617913
Intellectual disability syndromic and non-syndromic v0.1975 GEMIN4 Zornitza Stark reviewed gene: GEMIN4: Rating: AMBER; Mode of pathogenicity: None; Publications: 25558065, 30237576; Phenotypes: Neurodevelopmental disorder with microcephaly, cataracts, and renal abnormalities, MIM# 617913; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1968 GABRA2 Zornitza Stark gene: GABRA2 was added
gene: GABRA2 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: GABRA2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: GABRA2 were set to 29422393; 29961870; 31032849; 31032848
Phenotypes for gene: GABRA2 were set to Epileptic encephalopathy, early infantile, 78, 618557
Review for gene: GABRA2 was set to GREEN
gene: GABRA2 was marked as current diagnostic
Added comment: Six unrelated families reported, ID is part of the phenotype.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1965 HNRNPU Zornitza Stark Phenotypes for gene: HNRNPU were changed from to Epileptic encephalopathy, early infantile, 54, MIM#617391
Intellectual disability syndromic and non-syndromic v0.1962 HNRNPU Zornitza Stark reviewed gene: HNRNPU: Rating: GREEN; Mode of pathogenicity: None; Publications: 28944577, 28393272; Phenotypes: Epileptic encephalopathy, early infantile, 54, MIM#617391; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1949 FRRS1L Zornitza Stark gene: FRRS1L was added
gene: FRRS1L was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: FRRS1L was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FRRS1L were set to 27236917; 27239025
Phenotypes for gene: FRRS1L were set to Epileptic encephalopathy, early infantile, 37, MIM#616981
Review for gene: FRRS1L was set to GREEN
Added comment: Five unrelated individuals reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1888 DENND5A Zornitza Stark gene: DENND5A was added
gene: DENND5A was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: DENND5A was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DENND5A were set to 27431290; 27866705
Phenotypes for gene: DENND5A were set to Epileptic encephalopathy, early infantile, 49, MIM# 617281
Review for gene: DENND5A was set to GREEN
Added comment: Four unrelated families, ID is part of the phenotype.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1872 COL1A2 Zornitza Stark Phenotypes for gene: COL1A2 were changed from to Ehlers-Danlos syndrome, arthrochalasia type, 2, MIM# 617821; Ehlers-Danlos syndrome, cardiac valvular type, MIM# 225320; Osteogenesis imperfecta, type II, MIM# 166210; Osteogenesis imperfecta, type III, MIM# 259420; Osteogenesis imperfecta, type IV, MIM# 166220
Intellectual disability syndromic and non-syndromic v0.1869 COL1A2 Zornitza Stark reviewed gene: COL1A2: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Ehlers-Danlos syndrome, arthrochalasia type, 2, MIM# 617821, Ehlers-Danlos syndrome, cardiac valvular type, MIM# 225320, Osteogenesis imperfecta, type II, MIM# 166210, Osteogenesis imperfecta, type III, MIM# 259420, Osteogenesis imperfecta, type IV, MIM# 166220; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1823 EBP Zornitza Stark Added comment: Comment when marking as ready: CDP lethal in males (unless mosaic) and females generally have normal intellectual development. Hypomorphic variants in males result in MEND, which has ID as a feature (carrier females for these variants generally asymptomatic).
Intellectual disability syndromic and non-syndromic v0.1815 TUBGCP6 Zornitza Stark Phenotypes for gene: TUBGCP6 were changed from to Microcephaly and chorioretinopathy, autosomal recessive, 1, MIM#251270
Intellectual disability syndromic and non-syndromic v0.1812 TUBGCP6 Zornitza Stark reviewed gene: TUBGCP6: Rating: GREEN; Mode of pathogenicity: None; Publications: 25344692, 22279524; Phenotypes: Microcephaly and chorioretinopathy, autosomal recessive, 1, MIM#251270; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1795 GNAO1 Zornitza Stark Phenotypes for gene: GNAO1 were changed from Epileptic encephalopathy, early infantile, 17; Neurodevelopmental disorder with involuntary movements to Epileptic encephalopathy, early infantile, 17; Neurodevelopmental disorder with involuntary movements
Intellectual disability syndromic and non-syndromic v0.1794 GNAO1 Zornitza Stark Phenotypes for gene: GNAO1 were changed from to Epileptic encephalopathy, early infantile, 17; Neurodevelopmental disorder with involuntary movements
Intellectual disability syndromic and non-syndromic v0.1790 GNAO1 Zornitza Stark reviewed gene: GNAO1: Rating: GREEN; Mode of pathogenicity: Other; Publications: 28747448, 30682224; Phenotypes: Epileptic encephalopathy, early infantile, 17, Neurodevelopmental disorder with involuntary movements; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1789 CAD Zornitza Stark gene: CAD was added
gene: CAD was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: CAD was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CAD were set to 25678555; 28007989; 30914295
Phenotypes for gene: CAD were set to Epileptic encephalopathy, early infantile, 50, MIM# MIM 616457
Review for gene: CAD was set to GREEN
gene: CAD was marked as current diagnostic
Added comment: Four unrelated families (two with same variant and Roma background, likely founder).
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1769 BMPER Zornitza Stark edited their review of gene: BMPER: Added comment: Perinatal lethal skeletal dysplasia, not appropriate for this panel.; Changed rating: RED
Intellectual disability syndromic and non-syndromic v0.1764 ATP6V1A Zornitza Stark gene: ATP6V1A was added
gene: ATP6V1A was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: ATP6V1A was set to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Publications for gene: ATP6V1A were set to 29668857; 28065471
Phenotypes for gene: ATP6V1A were set to Epileptic encephalopathy, infantile or early childhood, 3 618012; Cutis laxa, autosomal recessive, type IID 617403
Mode of pathogenicity for gene: ATP6V1A was set to Other
Review for gene: ATP6V1A was set to GREEN
gene: ATP6V1A was marked as current diagnostic
Added comment: Both mono-allelic and bi-allelic variants associated with ID, evidence for both LoF and GoF for the mono-allelic variants.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1718 CNOT1 Sebastian Lunke gene: CNOT1 was added
gene: CNOT1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: CNOT1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CNOT1 were set to 31006510; 21679367; 31006513
Phenotypes for gene: CNOT1 were set to Holoprosencephaly 12, with or without pancreatic agenesis 618500
Review for gene: CNOT1 was set to GREEN
gene: CNOT1 was marked as current diagnostic
Added comment: From GEL: More than three independent families previously described
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1717 CCDC88C Sebastian Lunke Phenotypes for gene: CCDC88C were changed from Spinocerebellar ataxia 40, MIM#616053 to Hydrocephalus, nonsyndromic, autosomal recessive 236600 AR
Intellectual disability syndromic and non-syndromic v0.1714 CCDC88C Sebastian Lunke reviewed gene: CCDC88C: Rating: GREEN; Mode of pathogenicity: None; Publications: 23042809, 21031079; Phenotypes: Hydrocephalus, nonsyndromic, autosomal recessive 236600 AR; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.1702 SLC6A9 Zornitza Stark Phenotypes for gene: SLC6A9 were changed from Glycine encephalopathy with normal serum glycine 617301 to Glycine encephalopathy with normal serum glycine 617301
Intellectual disability syndromic and non-syndromic v0.1701 SLC6A9 Zornitza Stark Phenotypes for gene: SLC6A9 were changed from to Glycine encephalopathy with normal serum glycine 617301
Intellectual disability syndromic and non-syndromic v0.1699 SLC6A9 Zornitza Stark reviewed gene: SLC6A9: Rating: GREEN; Mode of pathogenicity: None; Publications: 27481395, 27773429; Phenotypes: Glycine encephalopathy with normal serum glycine 617301; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.1684 VPS11 Zornitza Stark gene: VPS11 was added
gene: VPS11 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: VPS11 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: VPS11 were set to 27120463; 26307567; 27473128
Phenotypes for gene: VPS11 were set to Leukodystrophy, hypomyelinating, 12, MIM#616683
Review for gene: VPS11 was set to GREEN
Added comment: ID, (variable) acquired microcephaly with hypomyelination; seizures in several reported individuals. 13 individuals from 7 Ashkenazi Jewish families, homozygous for a founder mutation (NM_021729.5:c.2536T>G or p.Cys846Gly); a different variant (p.Leu387_Gly395del) reported in a consanguineous family.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1681 TRAPPC12 Zornitza Stark Phenotypes for gene: TRAPPC12 were changed from to Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, MIM#617669
Intellectual disability syndromic and non-syndromic v0.1679 TRAPPC12 Zornitza Stark reviewed gene: TRAPPC12: Rating: AMBER; Mode of pathogenicity: None; Publications: 28777934; Phenotypes: Encephalopathy, progressive, early-onset, with brain atrophy and spasticity, MIM#617669; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1677 SLC1A4 Zornitza Stark gene: SLC1A4 was added
gene: SLC1A4 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: SLC1A4 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SLC1A4 were set to 29989513; 27193218; 26138499; 26041762; 25930971
Phenotypes for gene: SLC1A4 were set to Spastic tetraplegia, thin corpus callosum, and progressive microcephaly, MIM# 616657
Review for gene: SLC1A4 was set to GREEN
gene: SLC1A4 was marked as current diagnostic
Added comment: Multiple affected individuals reported in the literature, seizures/EE are part of the phenotype. While initial reports identified a recurrent missense variant in individuals of Ashkenazi Jewish ancestry, there have been more recent reports of individuals from other ethnic backgrounds with different variants
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1673 MACF1 Zornitza Stark gene: MACF1 was added
gene: MACF1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: MACF1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MACF1 were set to 30471716
Phenotypes for gene: MACF1 were set to Lissencephaly 9 with complex brainstem malformation, MIM# 618325
Mode of pathogenicity for gene: MACF1 was set to Loss-of-function variants (as defined in pop up message) DO NOT cause this phenotype - please provide details in the comments
Review for gene: MACF1 was set to GREEN
Added comment: Nine individuals (including a pair of twins) reported with de novo, likely GoF variants in this gene.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1666 KATNB1 Zornitza Stark gene: KATNB1 was added
gene: KATNB1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: KATNB1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: KATNB1 were set to 25521378; 25521379; 26640080
Phenotypes for gene: KATNB1 were set to Lissencephaly 6, with microcephaly, MIM# 616212
Review for gene: KATNB1 was set to GREEN
Added comment: At least 9 families reported with bi-allelic variants in this gene.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1664 GNB5 Zornitza Stark gene: GNB5 was added
gene: GNB5 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list
Mode of inheritance for gene: GNB5 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GNB5 were set to 27523599; 27677260; 28697420; 29368331
Phenotypes for gene: GNB5 were set to Intellectual developmental disorder with cardiac arrhythmia, 617173; Language delay and ADHD/cognitive impairment with or without cardiac arrhythmia, 617182; Early infantile epileptic encephalopathy (EIEE)
Review for gene: GNB5 was set to GREEN
gene: GNB5 was marked as current diagnostic
Added comment: Multiple affected individuals reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1658 GOT2 Zornitza Stark gene: GOT2 was added
gene: GOT2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: GOT2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: GOT2 were set to 31422819
Phenotypes for gene: GOT2 were set to Epileptic encephalopathy, early infantile, 82, MIM# 618721
Review for gene: GOT2 was set to GREEN
Added comment: Four individuals from three unrelated families reported, EE/DD. Treatment with pyridoxine and serine ameliorated the phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1641 MTHFS Zornitza Stark gene: MTHFS was added
gene: MTHFS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: MTHFS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MTHFS were set to 30031689; 31844630; 22303332
Phenotypes for gene: MTHFS were set to Neurodevelopmental disorder with microcephaly, epilepsy, and hypomyelination, 618367
Review for gene: MTHFS was set to GREEN
Added comment: Three unrelated individuals reported with supporting biochemical evidence.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1632 TUBGCP2 Zornitza Stark gene: TUBGCP2 was added
gene: TUBGCP2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TUBGCP2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TUBGCP2 were set to 31630790
Phenotypes for gene: TUBGCP2 were set to Lissencephaly; pachygyria; subcortical band heterotopia; microcephaly; intellectual disability
Review for gene: TUBGCP2 was set to GREEN
Added comment: Four unrelated families reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1630 TP73 Zornitza Stark gene: TP73 was added
gene: TP73 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: TP73 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TP73 were set to 31130284
Phenotypes for gene: TP73 were set to Intellectual disability; lissencephaly
Review for gene: TP73 was set to AMBER
Added comment: Two unrelated families, no functional data.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1607 CARS Alison Yeung gene: CARS was added
gene: CARS was added to Intellectual disability syndromic and non-syndromic. Sources: Literature
Mode of inheritance for gene: CARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CARS were set to PMID: 30824121
Phenotypes for gene: CARS were set to Intellectual disability; microcephaly; brittle hair and nails
Review for gene: CARS was set to GREEN
gene: CARS was marked as current diagnostic
Added comment: Three reported unrelated families
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1592 HK1 Natasha Brown gene: HK1 was added
gene: HK1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: HK1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: HK1 were set to PMID: 30778173
Mode of pathogenicity for gene: HK1 was set to Other
Review for gene: HK1 was set to GREEN
Added comment: 7 patients from 6 unrelated families with denovo missense variants in the N-terminal half of HK1
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1591 SNORD118 Zornitza Stark Phenotypes for gene: SNORD118 were changed from to Leukoencephalopathy, brain calcifications, and cysts, MIM#614561
Intellectual disability syndromic and non-syndromic v0.1587 FARSB Zornitza Stark gene: FARSB was added
gene: FARSB was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Expert list
Mode of inheritance for gene: FARSB was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FARSB were set to 29573043; 19161147; 29979980; 30014610
Phenotypes for gene: FARSB were set to Rajab syndrome, MIM#613658; interstitial lung disease; brain calcifications; microcephaly; intellectual disability
Review for gene: FARSB was set to GREEN
Added comment: 7 unrelated families reported.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1571 MED17 Zornitza Stark Phenotypes for gene: MED17 were changed from to Microcephaly, postnatal progressive, with seizures and brain atrophy, MIM#613668
Intellectual disability syndromic and non-syndromic v0.1552 SMPD4 Zornitza Stark Phenotypes for gene: SMPD4 were changed from Severe neurodevelopmental delay, microcephaly, arthrogryposis to Severe neurodevelopmental delay, microcephaly, arthrogryposis
Intellectual disability syndromic and non-syndromic v0.1551 SMPD4 Zornitza Stark Phenotypes for gene: SMPD4 were changed from to Severe neurodevelopmental delay, microcephaly, arthrogryposis
Intellectual disability syndromic and non-syndromic v0.1548 TBCD Zornitza Stark Phenotypes for gene: TBCD were changed from Encephalopathy, progressive, early-onset, with brain atrophy and thin corpus callosum, MIM#617193 to Encephalopathy, progressive, early-onset, with brain atrophy and thin corpus callosum, MIM#617193
Intellectual disability syndromic and non-syndromic v0.1548 TBCD Zornitza Stark Phenotypes for gene: TBCD were changed from to Encephalopathy, progressive, early-onset, with brain atrophy and thin corpus callosum, MIM#617193
Intellectual disability syndromic and non-syndromic v0.1536 AGMO Sue White gene: AGMO was added
gene: AGMO was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: AGMO was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: AGMO were set to 31555905
Phenotypes for gene: AGMO were set to microcephaly; intellectual disability; epilepsy
Penetrance for gene: AGMO were set to Complete
Review for gene: AGMO was set to GREEN
Added comment: biallelic missense and LOF variants reported
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1526 NUP214 Zornitza Stark Phenotypes for gene: NUP214 were changed from epileptic encephalopathy; developmental regression; microcephaly to {Encephalopathy, acute, infection-induced, susceptibility to, 9}, MIM# 618426; epileptic encephalopathy; developmental regression; microcephaly
Intellectual disability syndromic and non-syndromic v0.1524 NUP214 Sue White gene: NUP214 was added
gene: NUP214 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: NUP214 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NUP214 were set to 31178128
Phenotypes for gene: NUP214 were set to epileptic encephalopathy; developmental regression; microcephaly
Penetrance for gene: NUP214 were set to Complete
Review for gene: NUP214 was set to GREEN
gene: NUP214 was marked as current diagnostic
Added comment: Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1517 WDFY3 Zornitza Stark Phenotypes for gene: WDFY3 were changed from to Microcephaly 18, primary, autosomal dominant, MIM#617520
Intellectual disability syndromic and non-syndromic v0.1514 DNMT3A Zornitza Stark Phenotypes for gene: DNMT3A were changed from Gatton-Brown-Rahman syndrome, MIM#615879; primordial dwarfism with intellectual disability and microcephaly to Tatton-Brown-Rahman syndrome, MIM#615879; primordial dwarfism with intellectual disability and microcephaly
Intellectual disability syndromic and non-syndromic v0.1513 DNMT3A Zornitza Stark Phenotypes for gene: DNMT3A were changed from to Gatton-Brown-Rahman syndrome, MIM#615879; primordial dwarfism with intellectual disability and microcephaly
Intellectual disability syndromic and non-syndromic v0.1510 DNMT3A Zornitza Stark reviewed gene: DNMT3A: Rating: GREEN; Mode of pathogenicity: Other; Publications: 30478443, 24614070; Phenotypes: TATTON-BROWN-RAHMAN SYNDROME, OMIM# 615879, primordial dwarfism with intellectual disability and microcephaly; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1501 PUS3 Zornitza Stark gene: PUS3 was added
gene: PUS3 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Expert list
Mode of inheritance for gene: PUS3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PUS3 were set to 30308082; 28454995; 27055666; 30697592; 31444731
Phenotypes for gene: PUS3 were set to Mental retardation, autosomal recessive 55, MIM# 617051
Review for gene: PUS3 was set to GREEN
Added comment: Seven individuals from five families reported; two of the families had the same homozygous truncating variant. Variable features reported in addition to ID, including leukoencephalopathy, EE, and nephropathy.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1486 ODC1 Zornitza Stark gene: ODC1 was added
gene: ODC1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: ODC1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: ODC1 were set to 30475435
Phenotypes for gene: ODC1 were set to Intellectual disability; macrocephaly; dysmorphism
Mode of pathogenicity for gene: ODC1 was set to Other
Review for gene: ODC1 was set to GREEN
Added comment: Four individuals with de novo GoF variants in this gene reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1476 UGP2 Zornitza Stark gene: UGP2 was added
gene: UGP2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: UGP2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: UGP2 were set to 31820119
Phenotypes for gene: UGP2 were set to Epileptic encephalopathy; intellectual disability; microcephaly
Review for gene: UGP2 was set to GREEN
Added comment: 22 individuals from 15 families reported with the same homozygous missense variant in this gene, chr2:64083454A > G, which causes a disruption of the start codon in the shorter isoform, which is expressed in brain.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1451 DMXL2 Zornitza Stark gene: DMXL2 was added
gene: DMXL2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: DMXL2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DMXL2 were set to 31688942; 30237576
Phenotypes for gene: DMXL2 were set to Epileptic encephalopathy, early infantile, 81, MIM# 618663
Review for gene: DMXL2 was set to GREEN
Added comment: Four unrelated families reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1447 NUP188 Zornitza Stark Phenotypes for gene: NUP188 were changed from to microcephaly; ID; cataract
Intellectual disability syndromic and non-syndromic v0.1444 NUP188 Zornitza Stark reviewed gene: NUP188: Rating: GREEN; Mode of pathogenicity: None; Publications: https://doi.org/10.1159/000504818, 28726809; Phenotypes: microcephaly, ID, cataract; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1440 COQ5 Zornitza Stark Phenotypes for gene: COQ5 were changed from to Cerebellar ataxia; encephalopathy; generalized tonic-clonic seizures; intellectual disability
Intellectual disability syndromic and non-syndromic v0.1436 COQ5 Zornitza Stark reviewed gene: COQ5: Rating: RED; Mode of pathogenicity: None; Publications: 29044765; Phenotypes: Cerebellar ataxia, encephalopathy, generalized tonic-clonic seizures, intellectual disability; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1435 MN1 Zornitza Stark gene: MN1 was added
gene: MN1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: MN1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: MN1 were set to 31834374; 31839203
Phenotypes for gene: MN1 were set to Intellectual disability; dysmophic features; rhombencephalosynapsis
Mode of pathogenicity for gene: MN1 was set to Other
Review for gene: MN1 was set to GREEN
Added comment: Over 20 individuals described with de novo truncating variants in this gene; these cluster in the C-terminal and the authors postulate that that syndrome is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1426 TASP1 Zornitza Stark gene: TASP1 was added
gene: TASP1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: TASP1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TASP1 were set to 31209944; 31350873
Phenotypes for gene: TASP1 were set to Developmental delay; microcephaly; dysmorphic features; congenital abnormalities
Review for gene: TASP1 was set to GREEN
Added comment: Four unrelated families reported; two with founder mutation. Protein interacts with KMT2A and KMT2D. Another infant with a de novo missense variant reported in a single infant with multiple congenital abnormalities, insufficient evidence for mono allelic disease at present.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1417 PPP1R12A Zornitza Stark gene: PPP1R12A was added
gene: PPP1R12A was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Research
Mode of inheritance for gene: PPP1R12A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: PPP1R12A were set to Intellectual disability; holoprosencephaly; disorder of sex development
Added comment: Emerging evidence.
Sources: Research
Intellectual disability syndromic and non-syndromic v0.1397 TENM3 Zornitza Stark gene: TENM3 was added
gene: TENM3 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: TENM3 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TENM3 were set to 30513139; 22766609; 27103084; 29753094
Phenotypes for gene: TENM3 were set to Microphthalmia, syndromic 15, MIM#615145; coloboma
Review for gene: TENM3 was set to GREEN
Added comment: At least four unrelated families described with syndromic microphthalmia and bi-allelic variants in this gene.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1394 PISD Zornitza Stark Phenotypes for gene: PISD were changed from no OMIM number yet. to Intellectual disability; cataracts; retinal degeneration; microcephaly; deafness; short stature; white matter abnormalities; no OMIM number yet.
Intellectual disability syndromic and non-syndromic v0.1374 DYNC1I2 Zornitza Stark gene: DYNC1I2 was added
gene: DYNC1I2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: DYNC1I2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DYNC1I2 were set to 31079899
Phenotypes for gene: DYNC1I2 were set to Neurodevelopmental disorder with microcephaly and structural brain anomalies , MIM#618492
Review for gene: DYNC1I2 was set to GREEN
Added comment: Five individuals from three unrelated families reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1373 DTYMK Zornitza Stark gene: DTYMK was added
gene: DTYMK was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: DTYMK was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: DTYMK were set to 31271740
Phenotypes for gene: DTYMK were set to Intellectual disability; microcephaly
Review for gene: DTYMK was set to RED
Added comment: Single family, two affected sibs with compound het variants reported.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1366 CYFIP2 Zornitza Stark gene: CYFIP2 was added
gene: CYFIP2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: CYFIP2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CYFIP2 were set to 29534297
Phenotypes for gene: CYFIP2 were set to Epileptic encephalopathy, early infantile, 65, MIM#618008
Review for gene: CYFIP2 was set to GREEN
Added comment: Four unrelated individuals with de novo variants in this gene. All variants affected the same highly conserved residue (arg87) in the DUF1394 domain.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1364 CSDE1 Zornitza Stark gene: CSDE1 was added
gene: CSDE1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: CSDE1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CSDE1 were set to 31579823
Phenotypes for gene: CSDE1 were set to Autism; intellectual disability; seizures; macrocephaly
Review for gene: CSDE1 was set to GREEN
Added comment: 18 families reported with high impact (stoppage/frameshift) variants in this gene. Eight de novo, eight inherited, two with undetermined inheritance. Functional data. Parents who had the variants were also affected, though generally more mildly.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1363 FAM160B1 Chirag Patel gene: FAM160B1 was added
gene: FAM160B1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: FAM160B1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FAM160B1 were set to PMID: 31353455; 27431290
Phenotypes for gene: FAM160B1 were set to no OMIM number yet
Review for gene: FAM160B1 was set to RED
Added comment: 1 patient with severe ID, microcephaly, behavioral abnormalities, speech problems, mild ataxia and mild facial dysmorphism, and homozygous truncating variant in FAM160B1. No functional studies.

1 family with 2 sibs with DD, ID, speech issues, and with homozygous missense variant in FAM160B1. No functional studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1363 FAM160B1 Chirag Patel gene: FAM160B1 was added
gene: FAM160B1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: FAM160B1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: FAM160B1 were set to PMID: 31353455; 27431290
Phenotypes for gene: FAM160B1 were set to no OMIM number yet
Review for gene: FAM160B1 was set to RED
Added comment: 1 patient with severe ID, microcephaly, behavioral abnormalities, speech problems, mild ataxia and mild facial dysmorphism, and homozygous truncating variant in FAM160B1. No functional studies.

1 family with 2 sibs with DD, ID, speech issues, and with homozygous missense variant in FAM160B1. No functional studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1355 GABRA5 Chirag Patel gene: GABRA5 was added
gene: GABRA5 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: GABRA5 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: GABRA5 were set to PMID: 31056671; 29961870
Phenotypes for gene: GABRA5 were set to Epileptic encephalopathy, early infantile, 79; OMIM #618559
Review for gene: GABRA5 was set to GREEN
Added comment: 3 unrelated patients with de novo heterozygous missense mutations in GABRA5 gene. In vitro functional expression studies in HEK293 cells showed that the mutant subunit was expressed at the surface and incorporated into the channel, but the mutant channel was 10 times more sensitive to GABA compared to wildtype. This increased sensitization resulted in increased receptor desensitization to GABA, with a reduced maximal GABA-evoked current and impaired capacity to pass GABAergic chloride current.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1354 ADGRG6 Chirag Patel gene: ADGRG6 was added
gene: ADGRG6 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: ADGRG6 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ADGRG6 were set to PMID: 30549416
Phenotypes for gene: ADGRG6 were set to Lethal congenital contracture syndrome 9; OMIM #616503
Review for gene: ADGRG6 was set to RED
Added comment: 1 family with 2 patients with profound ID, severe speech impairment, microcephaly, seizures, spasticity, and cerebellar hypoplasia, with homozygous missense variation in ADGRG6 (GPR126). No functional studies.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1340 MACROD2 Chirag Patel gene: MACROD2 was added
gene: MACROD2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: MACROD2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MACROD2 were set to PMID: 31055587
Phenotypes for gene: MACROD2 were set to no OMIM number yet
Review for gene: MACROD2 was set to RED
Added comment: 1 family with a few affected with microcephaly, ID, dysmorphic features, and polydactyly. Deletion of chromosome 20p12.1 involving the MACROD2 gene was found in several members of the family. qRT-PCR showed higher levels of a MACROD2 mRNA isoform in the individuals carrying the deletion.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1338 MAST1 Chirag Patel gene: MAST1 was added
gene: MAST1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: MAST1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: MAST1 were set to PMID: 31721002; 30449657
Phenotypes for gene: MAST1 were set to Mega-corpus-callosum syndrome with cerebellar hypoplasia and cortical malformations; OMIM #618273
Review for gene: MAST1 was set to GREEN
Added comment: 6 unrelated patients with mega-corpus-callosum syndrome with cerebellar hypoplasia and cortical malformations (MCCCHCM) with de novo heterozygous mutations in MAST1 gene. In vitro functional studies showed that 1 of the variants (lys276del) increased MAST1 binding to microtubules compared to controls. Mutant mice heterozygous for a Mast1 leu278del allele showed a thicker corpus callosum compared to wildtype, and an overall reduction in cortical volume and thickness and decreased cerebellar volume and number of granule and Purkinje cells due to increased apoptosis compared to controls.

1 Emirati patient with ID, microcephaly, and dysmorphic features, with missense variant in MAST1.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1335 NCAPD2 Chirag Patel gene: NCAPD2 was added
gene: NCAPD2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: NCAPD2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: NCAPD2 were set to PMID: 31056748; 27737959; 28097321
Phenotypes for gene: NCAPD2 were set to ?Microcephaly 21, primary, autosomal recessive; OMIM #617983
Review for gene: NCAPD2 was set to AMBER
Added comment: 1 family with 2 sibs with microcephaly and ID, and homozygous NCAPD2 mutation, which segregated with disease. No functional evidence.

1 family with 1 affected and homozygous NCAPD2 mutation, which segregated with disease. Patient fibroblasts showed impaired chromosome segregation and abnormal recovery from mitotic condensation compared to controls.

1 family with 2 sibs with microcephaly, growth retardation, and ID, and homozygous NCAPD2 mutation, which segregated with disease. Functional studies of the variants and studies of patient cells were not performed.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1328 PAK1 Chirag Patel gene: PAK1 was added
gene: PAK1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: PAK1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: PAK1 were set to PMID: 31504246; 30290153
Phenotypes for gene: PAK1 were set to Intellectual developmental disorder with macrocephaly, seizures, and speech delay; OMIM #618158
Review for gene: PAK1 was set to GREEN
Added comment: 2 unrelated individuals with de novo PAK1 mutations, with developmental delay, secondary macrocephaly, seizures, and ataxic gait. Enhanced phosphorylation of the PAK1 targets JNK and AKT shown in fibroblasts of one subject and of c-JUN in those of both subjects compared with control subjects. In fibroblasts of the 2 affected individuals, they observed a trend toward enhanced PAK1 kinase activity. By using co-immunoprecipitation and size-exclusion chromatography, they observed a significantly reduced dimerization for both PAK1 mutants compared with wild-type PAK1.

4 unrelated individuals with intellectual disability, macrocephaly and seizures, with de novo heterozygous missense variants in PAK1.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1322 PIGB Chirag Patel gene: PIGB was added
gene: PIGB was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: PIGB was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PIGB were set to PubMed: 31256876
Phenotypes for gene: PIGB were set to Epileptic encephalopathy, early infantile, 80; OMIM #618580
Review for gene: PIGB was set to GREEN
Added comment: 10 unrelated families with biallelic mutations in PIGB, with global DD and/or ID, and seizures. Two had polymicrogyria, 4 had a peripheral neuropathy, and 2 had a clinical diagnosis of DOORS syndrome. Patient lymphocytes and fibroblasts showed variably decreased levels of cell surface GPI-anchored proteins, including CD16 and CD59. In vitro functional expression studies performed with some of the mutations in PIGB-null CHO cells showed that the mutant proteins were unable to fully restore expression of GPI-anchored surface proteins, consistent with a loss of function, although the mutations had variable effects.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1317 PISD Chirag Patel changed review comment from: 4 individuals in 2 unrelated but consanguineous families from Portugal and Brazil affected by early-onset retinal degeneration, sensorineural hearing loss, microcephaly, intellectual disability, and skeletal dysplasia with scoliosis and short stature (Liberfarb syndrome). Affected individuals shared a homozygous 10-bp deletion immediately upstream of the last exon of the PISD gene. In HEK293T cells, this variant led to aberrant splicing of PISD transcripts.
Sources: Literature; to: 4 individuals in 2 unrelated but consanguineous families from Portugal and Brazil affected by early-onset retinal degeneration, sensorineural hearing loss, microcephaly, intellectual disability, and skeletal dysplasia with scoliosis and short stature (Liberfarb syndrome). Affected individuals shared a homozygous 10-bp deletion immediately upstream of the last exon of the PISD gene. In HEK293T cells, this variant led to aberrant splicing of PISD transcripts.

1 family with 2 sisters with congenital cataracts, short stature, and white matter changes identified compound heterozygous variants in the PISD gene. Decreased conversion of phosphatidylserine to PE in patient fibroblasts is consistent with impaired phosphatidylserine decarboxylase (PISD) enzyme activity.
Intellectual disability syndromic and non-syndromic v0.1317 PISD Chirag Patel gene: PISD was added
gene: PISD was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: PISD was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PISD were set to PMID: 31263216
Phenotypes for gene: PISD were set to no OMIM number yet.
Review for gene: PISD was set to AMBER
Added comment: 4 individuals in 2 unrelated but consanguineous families from Portugal and Brazil affected by early-onset retinal degeneration, sensorineural hearing loss, microcephaly, intellectual disability, and skeletal dysplasia with scoliosis and short stature (Liberfarb syndrome). Affected individuals shared a homozygous 10-bp deletion immediately upstream of the last exon of the PISD gene. In HEK293T cells, this variant led to aberrant splicing of PISD transcripts.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1311 PUS7 Chirag Patel gene: PUS7 was added
gene: PUS7 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: PUS7 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: PUS7 were set to PMID: 30526862; 30778726; 31583274
Phenotypes for gene: PUS7 were set to Intellectual developmental disorder with abnormal behavior, microcephaly, and short stature; OMIM #618342
Review for gene: PUS7 was set to GREEN
Added comment: 11 patients from 6 families with ID, speech delay, short stature, microcephaly, and aggressive behavior, with homozygous PUS7 mutations, which segregated with disease.

One study showed disease-related variants lead to abolishment of PUS7 activity on both tRNA and mRNA substrates. pus7 knockout in Drosophila melanogaster results in a number of behavioral defects, including increased activity, disorientation, and aggressiveness supporting that neurological defects are caused by PUS7 variants.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1309 RNF113A Chirag Patel gene: RNF113A was added
gene: RNF113A was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: RNF113A was set to X-LINKED: hemizygous mutation in males, monoallelic mutations in females may cause disease (may be less severe, later onset than males)
Publications for gene: RNF113A were set to PMID: 25612912; 31793730
Phenotypes for gene: RNF113A were set to ?Trichothiodystrophy 5, nonphotosensitive; OMIM #300953
Review for gene: RNF113A was set to AMBER
Added comment: 1 family of 2 male cousins with IUGR, progressive microcephaly, profound ID, genital anomalies, and severe linear growth failure, and nonsense Q301X mutation in RNF113A gene. Segregated with disease in the family. The mutation markedly reduced RNF113A protein expression in extracts from lymphoblastoid cell lines derived from the affected individuals.

2 fetuses affected with abnormalities similar to previous report, with the same nonsense Q301X mutation in RNF113A gene (can not access paper to see if from same family or functional evidence).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1293 SNRPE Chirag Patel gene: SNRPE was added
gene: SNRPE was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: SNRPE was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: SNRPE were set to Hypotrichosis 11; OMIM #615059
Review for gene: SNRPE was set to AMBER
Added comment: 1 patient with de novo heterozygous missense SNRPE mutation, with non-syndromic primary microcephaly and intellectual disability. SNRPE encodes SmE and they showed that the microcephaly-linked SmE variant is unable to interact with the SMN complex and as a consequence fails to assemble into U snRNPs. This results in widespread mRNA splicing alterations in fibroblast cells derived from this patient. Similar alterations were observed in HEK293 cells upon SmE depletion that could be rescued by the expression of wild type but not mutant SmE. Depletion of SmE in zebrafish causes aberrant mRNA splicing alterations and reduced brain size, reminiscent of the patient microcephaly phenotype.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1289 SVBP Chirag Patel gene: SVBP was added
gene: SVBP was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: SVBP was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SVBP were set to PMID: 31363758; 30607023
Phenotypes for gene: SVBP were set to Neurodevelopmental disorder with ataxia, hypotonia, and microcephaly; OMIM #618569
Review for gene: SVBP was set to GREEN
Added comment: 5 unrelated families with homozygous mutations in SVBP. The mutations segregated with the disorder in all families. In vitro functional cellular expression studies showed that protein levels of the SVBP mutants were barely detectable, suggesting instability, and that the mutant proteins had lost VASH/SVBP catalytic detyrosination activity toward tubulin. Knockdown of about 50% Svbp expression using shRNA in rat hippocampal neurons impaired the formation of excitatory synapses compared to controls.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1282 TEMN3-AS1 Chirag Patel changed review comment from: 3 unrelated families, but no functional evidence.
Sources: Literature; to: 3 unrelated families with DD/ID as part of syndromic microphthalmia, but no functional evidence.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1281 TEMN3-AS1 Chirag Patel gene: TEMN3-AS1 was added
gene: TEMN3-AS1 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: TEMN3-AS1 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TEMN3-AS1 were set to PubMed: 27103084; 30513139; 30513139
Phenotypes for gene: TEMN3-AS1 were set to ?Microphthalmia, isolated, with coloboma 9, OMIM #615145; Microphthalmia, syndromic 15, OMIM #615145
Review for gene: TEMN3-AS1 was set to AMBER
Added comment: 3 unrelated families, but no functional evidence.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1279 APC2 Zornitza Stark gene: APC2 was added
gene: APC2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: APC2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: APC2 were set to 31585108
Phenotypes for gene: APC2 were set to Cortical dysplasia, complex, with other brain malformations 10, MIM#618677
Review for gene: APC2 was set to GREEN
Added comment: 12 individuals from 8 unrelated families; intellectual disability, seizures, cortical dysplasia including posterior to anterior predominant pattern of lissencephaly, heterotopias, paucity of white matter, thin corpus callosum.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1277 VAMP2 Chirag Patel gene: VAMP2 was added
gene: VAMP2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: VAMP2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: VAMP2 were set to PMID: 30929742
Phenotypes for gene: VAMP2 were set to no OMIM number yet
Review for gene: VAMP2 was set to GREEN
Added comment: 5 unrelated patients with heterozygous de novo mutations in VAMP2, presenting with a neurodevelopmental disorder characterized by axial hypotonia, intellectual disability, and autistic features. Affected individuals carrying de novo non-synonymous variants involving the C-terminal region presented a more severe phenotype with additional neurological features, including central visual impairment, hyperkinetic movement disorder, and epilepsy or electroencephalography abnormalities. Reconstituted fusion involving a lipid-mixing assay indicated impairment in vesicle fusion as one of the possible associated disease mechanisms.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1268 ACTL6B Zornitza Stark gene: ACTL6B was added
gene: ACTL6B was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: ACTL6B was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: ACTL6B were set to 31134736; 31031012; 30656450; 30237576
Phenotypes for gene: ACTL6B were set to Epileptic encephalopathy, early infantile, 76, MIM# 618468; Intellectual developmental disorder with severe speech and ambulation defects, MIM# 618470
Review for gene: ACTL6B was set to GREEN
Added comment: Multiple affected individuals reported, main phenotype is ID/EE.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1252 SLC25A4 Chirag Patel reviewed gene: SLC25A4: Rating: ; Mode of pathogenicity: None; Publications: PMID: 30013777, 27693233; Phenotypes: Mitochondrial DNA depletion syndrome 12A (cardiomyopathic type) AD, OMIM #617184, Mitochondrial DNA depletion syndrome 12B (cardiomyopathic type) AR, OMIM #615418, Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 2, OMIM #609283; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1252 SLC25A4 Zornitza Stark Phenotypes for gene: SLC25A4 were changed from to Mitochondrial DNA depletion syndrome 12A (cardiomyopathic type) AD, MIM#617184; Mitochondrial DNA depletion syndrome 12B (cardiomyopathic type) AR, MIM#615418; Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 2, MIM#609283
Intellectual disability syndromic and non-syndromic v0.1249 SLC25A4 Zornitza Stark reviewed gene: SLC25A4: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Mitochondrial DNA depletion syndrome 12A (cardiomyopathic type) AD, MIM#617184, Mitochondrial DNA depletion syndrome 12B (cardiomyopathic type) AR, MIM#615418, Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 2, MIM#609283; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1233 SLC25A19 Zornitza Stark Phenotypes for gene: SLC25A19 were changed from to Microcephaly, Amish type, MIM#607196; Thiamine metabolism dysfunction syndrome 4 (progressive polyneuropathy type), MIM#613710
Intellectual disability syndromic and non-syndromic v0.1233 SMCHD1 Chirag Patel Source Genetic Health Queensland was removed from SMCHD1.
Source Expert list was added to SMCHD1.
Mode of inheritance for gene SMCHD1 was changed from Unknown to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes for gene: SMCHD1 were changed from to Bosma arhinia microphthalmia syndrome, OMIM #603457; Fascioscapulohumeral muscular dystrophy 2, digenic; OMIM #158901
Intellectual disability syndromic and non-syndromic v0.1231 SMCHD1 Chirag Patel reviewed gene: SMCHD1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Bosma arhinia microphthalmia syndrome, OMIM #603457, Fascioscapulohumeral muscular dystrophy 2, digenic, OMIM #158901; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1229 SLC25A19 Zornitza Stark reviewed gene: SLC25A19: Rating: AMBER; Mode of pathogenicity: None; Publications: 31506564, 31295743, 12185364, 19798730; Phenotypes: Microcephaly, Amish type, MIM#607196, Thiamine metabolism dysfunction syndrome 4 (progressive polyneuropathy type), MIM#613710; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1178 SUCLA2 Chirag Patel Source Genetic Health Queensland was removed from SUCLA2.
Source Expert list was added to SUCLA2.
Mode of inheritance for gene SUCLA2 was changed from Unknown to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: SUCLA2 were changed from to Mitochondrial DNA depletion syndrome 5 (encephalomyopathic with or without methylmalonic aciduria); OMIM #612073
Publications for gene SUCLA2 were changed from PMID: 27913098; 15877282; 23759946; 17287286; 17301081 to PMID: 27913098; 15877282; 23759946; 17287286; 17301081
Intellectual disability syndromic and non-syndromic v0.1177 SUCLA2 Chirag Patel reviewed gene: SUCLA2: Rating: GREEN; Mode of pathogenicity: None; Publications: PMID: 27913098, 15877282, 23759946, 17287286, 17301081; Phenotypes: Mitochondrial DNA depletion syndrome 5 (encephalomyopathic with or without methylmalonic aciduria), OMIM #612073; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1158 SELENOI Zornitza Stark gene: SELENOI was added
gene: SELENOI was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Expert list
Mode of inheritance for gene: SELENOI was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: SELENOI were set to 28052917
Phenotypes for gene: SELENOI were set to developmental delay; spasticity; periventricular white mater abnormalities; peripheral neuropathy; seizures; bifid uvula in some affected individuals; microcephaly
Review for gene: SELENOI was set to RED
Added comment: Single family only, four sibs, supportive biochemical evidence. Borderline amber/red gene, only mild ID described, seems to be more of a progressive neurometabolic condition based on limited evidence.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.1147 SCN1B Zornitza Stark Phenotypes for gene: SCN1B were changed from to Epileptic encephalopathy, early infantile, 52, MIM#617350
Intellectual disability syndromic and non-syndromic v0.1145 SCN1B Zornitza Stark reviewed gene: SCN1B: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Epileptic encephalopathy, early infantile, 52, MIM#617350; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1092 RNU4ATAC Zornitza Stark Phenotypes for gene: RNU4ATAC were changed from to Microcephalic osteodysplastic primordial dwarfism, type I, MIM#210710; Roifman syndrome, MIM#616651
Intellectual disability syndromic and non-syndromic v0.1090 RNU4ATAC Zornitza Stark reviewed gene: RNU4ATAC: Rating: GREEN; Mode of pathogenicity: Other; Publications: ; Phenotypes: Microcephalic osteodysplastic primordial dwarfism, type I, MIM#210710, Roifman syndrome, MIM#616651; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1087 RIN2 Zornitza Stark Phenotypes for gene: RIN2 were changed from to Macrocephaly, alopecia, cutis laxa, and scoliosis, MIM#613075
Intellectual disability syndromic and non-syndromic v0.1084 RIN2 Zornitza Stark reviewed gene: RIN2: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Macrocephaly, alopecia, cutis laxa, and scoliosis, MIM#613075; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.1083 RHOBTB2 Zornitza Stark gene: RHOBTB2 was added
gene: RHOBTB2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: RHOBTB2 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: RHOBTB2 were set to 29768694; 29276004
Phenotypes for gene: RHOBTB2 were set to Epileptic encephalopathy, early infantile, 64, MIM#618004
Review for gene: RHOBTB2 was set to GREEN
Added comment: 13 individuals from unrelated families reported in the literature in 2018 with de novo variants in this gene and ID/EE.
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.1051 RANBP2 Zornitza Stark Phenotypes for gene: RANBP2 were changed from to Encephalopathy, acute, infection-induced, 3, susceptibility to, MIM# 608033
Intellectual disability syndromic and non-syndromic v0.1048 RANBP2 Zornitza Stark reviewed gene: RANBP2: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Encephalopathy, acute, infection-induced, 3, susceptibility to, MIM# 608033; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.1026 PRRX1 Zornitza Stark Phenotypes for gene: PRRX1 were changed from to Agnathia-otocephaly complex, MIM#202650
Intellectual disability syndromic and non-syndromic v0.1024 PRRX1 Zornitza Stark reviewed gene: PRRX1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Agnathia-otocephaly complex, MIM#202650; Mode of inheritance: None
Intellectual disability syndromic and non-syndromic v0.952 PHC1 Zornitza Stark Phenotypes for gene: PHC1 were changed from to Microcephaly 11, primary, autosomal recessive, MIM#615414
Intellectual disability syndromic and non-syndromic v0.948 PHC1 Zornitza Stark reviewed gene: PHC1: Rating: AMBER; Mode of pathogenicity: None; Publications: 23418308; Phenotypes: Microcephaly 11, primary, autosomal recessive, MIM#615414; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.931 TMX2 Zornitza Stark gene: TMX2 was added
gene: TMX2 was added to Intellectual disability, syndromic and non-syndromic_GHQ_VCGS. Sources: Literature
Mode of inheritance for gene: TMX2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: TMX2 were set to 31735293; 31586943
Phenotypes for gene: TMX2 were set to Microcephaly; ID; brain malformations
Review for gene: TMX2 was set to GREEN
Added comment: 14 individuals from 10 unrelated families with bi-allelic variants in this gene (31735293) and another four families with recurrent variant (31586943).
Sources: Literature
Intellectual disability syndromic and non-syndromic v0.916 PCDH12 Zornitza Stark Phenotypes for gene: PCDH12 were changed from to Diencephalic-mesencephalic junction dysplasia syndrome 1, MIM#251280
Intellectual disability syndromic and non-syndromic v0.913 PCDH12 Zornitza Stark reviewed gene: PCDH12: Rating: GREEN; Mode of pathogenicity: None; Publications: 27164683, 30178464; Phenotypes: Diencephalic-mesencephalic junction dysplasia syndrome 1, MIM#251280; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.898 PACS2 Zornitza Stark Phenotypes for gene: PACS2 were changed from to Epileptic encephalopathy, early infantile, 66, MIM#618067
Intellectual disability syndromic and non-syndromic v0.895 PACS2 Zornitza Stark reviewed gene: PACS2: Rating: GREEN; Mode of pathogenicity: None; Publications: 29656858; Phenotypes: Epileptic encephalopathy, early infantile, 66, MIM#618067; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.877 NOTCH3 Zornitza Stark Phenotypes for gene: NOTCH3 were changed from to Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310
Intellectual disability syndromic and non-syndromic v0.874 NOTCH3 Zornitza Stark reviewed gene: NOTCH3: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Cerebral arteriopathy with subcortical infarcts and leukoencephalopathy 1, MIM#125310; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.866 NFIB Zornitza Stark gene: NFIB was added
gene: NFIB was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert list
Mode of inheritance for gene: NFIB was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: NFIB were set to 30388402
Phenotypes for gene: NFIB were set to Macrocephaly, acquired, with impaired intellectual development, MIM#618286
Review for gene: NFIB was set to GREEN
Added comment: 18 individuals reported, of whom 11 had deletions of this gene and the rest had SNVs.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.862 NECAP1 Zornitza Stark Phenotypes for gene: NECAP1 were changed from to Epileptic encephalopathy, early infantile, 21, MIM#615833
Intellectual disability syndromic and non-syndromic v0.858 NECAP1 Zornitza Stark reviewed gene: NECAP1: Rating: GREEN; Mode of pathogenicity: None; Publications: 24399846, 30626896, 30525121; Phenotypes: Epileptic encephalopathy, early infantile, 21, MIM#615833; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.814 CLCN2 Zornitza Stark Phenotypes for gene: CLCN2 were changed from to Leukoencephalopathy with ataxia, MIM#615651
Intellectual disability syndromic and non-syndromic v0.777 CDK6 Zornitza Stark Phenotypes for gene: CDK6 were changed from to Microcephaly 12, primary, autosomal recessive, MIM#616080
Intellectual disability syndromic and non-syndromic v0.535 KARS Zornitza Stark gene: KARS was added
gene: KARS was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert list
Mode of inheritance for gene: KARS was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: KARS were set to 26741492; 31618474; 28887846; 25330800; 29615062; 30252186; 28496994
Phenotypes for gene: KARS were set to Combined mitochondrial oxidative phosphorylation deficiency; epilepsy; intellectual disability; microcephaly
Review for gene: KARS was set to GREEN
gene: KARS was marked as current diagnostic
Added comment: Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.533 TREM2 Chirag Patel Source Genetic Health Queensland was removed from TREM2.
Source Expert list was added to TREM2.
Phenotypes for gene: TREM2 were changed from to Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy 2; OMIM #618193
Intellectual disability syndromic and non-syndromic v0.532 TREM2 Chirag Patel reviewed gene: TREM2: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy 2, OMIM #618193; Mode of inheritance: Unknown
Intellectual disability syndromic and non-syndromic v0.515 TUFM Chirag Patel edited their review of gene: TUFM: Added comment: Developmental regression seen as part of mitochondrial disorder - 3 families

1 patient with rapidly progressive encephalopathy and homozygous missense mutation in the TUFM gene. No functional studies.

2 families with 2 children each with COXPD4 and biallelic mutations in the TUFM gene. The mutations segregated with the disorder in the families. Complementation with wildtype TUFM restored the complex I and IV assembly and complex IV activity levels in fibroblasts from 1 of the patients.; Changed rating: AMBER
Intellectual disability syndromic and non-syndromic v0.514 TWNK Chirag Patel Source Genetic Health Queensland was removed from TWNK.
Source Expert list was added to TWNK.
Mode of inheritance for gene TWNK was changed from Unknown to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Phenotypes for gene: TWNK were changed from to Mitochondrial DNA depletion syndrome 7 (hepatocerebral type), OMIM #271245; Perrault syndrome 5, OMIM #616138; Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3, OMIM #609286
Intellectual disability syndromic and non-syndromic v0.513 TWNK Chirag Patel reviewed gene: TWNK: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Mitochondrial DNA depletion syndrome 7 (hepatocerebral type), OMIM #271245, Perrault syndrome 5, OMIM #616138, Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3, OMIM #609286; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.457 MYH3 Chirag Patel Source Genetic Health Queensland was removed from MYH3.
Source Expert list was added to MYH3.
Mode of inheritance for gene MYH3 was changed from Unknown to BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Phenotypes for gene: MYH3 were changed from to Arthrogryposis, distal, type 2A (Freeman-Sheldon), OMIM #193700; Arthrogryposis, distal, type 2B3 (Sheldon-Hall), OMIM #618436; Contractures, pterygia, and variable skeletal fusions syndrome 1A, OMIM #178110; Contractures, pterygia, and variable skeletal fusions syndrome 1B, OMIM #618469
Intellectual disability syndromic and non-syndromic v0.456 MYH3 Chirag Patel reviewed gene: MYH3: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Arthrogryposis, distal, type 2A (Freeman-Sheldon), OMIM #193700, Arthrogryposis, distal, type 2B3 (Sheldon-Hall), OMIM #618436, Contractures, pterygia, and variable skeletal fusions syndrome 1A, OMIM #178110, Contractures, pterygia, and variable skeletal fusions syndrome 1B, OMIM #618469; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.433 MPDZ Chirag Patel Source Genetic Health Queensland was removed from MPDZ.
Source Expert list was added to MPDZ.
Mode of inheritance for gene MPDZ was changed from Unknown to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: MPDZ were changed from to Hydrocephalus, congenital, 2, with or without brain or eye anomalies; OMIM #615219
Intellectual disability syndromic and non-syndromic v0.432 MPDZ Chirag Patel reviewed gene: MPDZ: Rating: GREEN; Mode of pathogenicity: None; Publications: PubMed: 28556411, 23240096; Phenotypes: Hydrocephalus, congenital, 2, with or without brain or eye anomalies, OMIM #615219; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.411 HYLS1 Zornitza Stark Phenotypes for gene: HYLS1 were changed from to Hydrolethalus syndrome, MIM#236680
Intellectual disability syndromic and non-syndromic v0.408 HYLS1 Zornitza Stark reviewed gene: HYLS1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Hydrolethalus syndrome, MIM#236680; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.394 HAL Zornitza Stark Marked gene: HAL as ready
Intellectual disability syndromic and non-syndromic v0.394 HAL Zornitza Stark Gene: hal has been classified as Red List (Low Evidence).
Intellectual disability syndromic and non-syndromic v0.394 HAL Zornitza Stark Phenotypes for gene: HAL were changed from to [Histidinemia], MIM#235800
Intellectual disability syndromic and non-syndromic v0.393 HAL Zornitza Stark Publications for gene: HAL were set to
Intellectual disability syndromic and non-syndromic v0.392 HAL Zornitza Stark Mode of inheritance for gene: HAL was changed from Unknown to BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.391 HAL Zornitza Stark Classified gene: HAL as Red List (low evidence)
Intellectual disability syndromic and non-syndromic v0.391 HAL Zornitza Stark Gene: hal has been classified as Red List (Low Evidence).
Intellectual disability syndromic and non-syndromic v0.390 HAL Zornitza Stark reviewed gene: HAL: Rating: RED; Mode of pathogenicity: None; Publications: 4421298, 7119955; Phenotypes: [Histidinemia], MIM#235800; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.387 UFM1 Chirag Patel commented on gene: UFM1: 20 families reported with encephalopathy/ID phenotype with functional studies.
Intellectual disability syndromic and non-syndromic v0.369 VARS2 Chirag Patel edited their review of gene: VARS2: Added comment: Multiple patients reported with ID, encephalopathy as part of this mitochondrial disorder.; Changed rating: GREEN; Changed publications: PubMed: 24827421, 25058219, 29137650, 29314548, 31064326
Intellectual disability syndromic and non-syndromic v0.303 ZNF335 Chirag Patel Source Genetic Health Queensland was removed from ZNF335.
Source Expert list was added to ZNF335.
Mode of inheritance for gene ZNF335 was changed from Unknown to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: ZNF335 were changed from to Microcephaly 10, primary, autosomal recessive; OMIM #615095
Intellectual disability syndromic and non-syndromic v0.302 ZNF335 Chirag Patel reviewed gene: ZNF335: Rating: GREEN; Mode of pathogenicity: None; Publications: PubMed: 23178126, 27540107, 29652087; Phenotypes: Microcephaly 10, primary, autosomal recessive, OMIM #615095; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.276 GCSH Zornitza Stark Phenotypes for gene: GCSH were changed from Glycine encephalopathy, MIM#605899 to Glycine encephalopathy, MIM#605899
Intellectual disability syndromic and non-syndromic v0.275 GCSH Zornitza Stark Phenotypes for gene: GCSH were changed from to Glycine encephalopathy, MIM#605899
Intellectual disability syndromic and non-syndromic v0.272 GCSH Zornitza Stark reviewed gene: GCSH: Rating: RED; Mode of pathogenicity: None; Publications: 1671321; Phenotypes: Glycine encephalopathy, MIM#605899; Mode of inheritance: None
Intellectual disability syndromic and non-syndromic v0.258 GATA1 Zornitza Stark reviewed gene: GATA1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Thrombocytopenia, X-linked, with or without dyserythropoietic anaemia, MIM#300367, Thrombocytopenia with beta-thalassemia, X-linked, MIM#314050, Anemia, X-linked, with/without neutropenia and/or platelet abnormalities, MIM#300835; Mode of inheritance: X-LINKED: hemizygous mutation in males, biallelic mutations in females
Intellectual disability syndromic and non-syndromic v0.201 EXT2 Zornitza Stark Phenotypes for gene: EXT2 were changed from to Seizures, scoliosis, and macrocephaly syndrome, MIM#616682
Intellectual disability syndromic and non-syndromic v0.199 EXT2 Zornitza Stark reviewed gene: EXT2: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Seizures, scoliosis, and macrocephaly syndrome, MIM#616682; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.167 EOMES Zornitza Stark Phenotypes for gene: EOMES were changed from to Microcephaly
Intellectual disability syndromic and non-syndromic v0.163 EOMES Zornitza Stark reviewed gene: EOMES: Rating: RED; Mode of pathogenicity: None; Publications: 17353897; Phenotypes: Microcephaly; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.159 EIF2B5 Zornitza Stark Phenotypes for gene: EIF2B5 were changed from to Leukoencephalopathy with vanishing white matter, MIM#603896
Intellectual disability syndromic and non-syndromic v0.156 EIF2B5 Zornitza Stark reviewed gene: EIF2B5: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leukoencephalopathy with vanishing white matter, MIM#603896; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.156 EIF2B4 Zornitza Stark Phenotypes for gene: EIF2B4 were changed from to Leukoencephalopathy with vanishing white matter, MIM#603896
Intellectual disability syndromic and non-syndromic v0.153 EIF2B4 Zornitza Stark reviewed gene: EIF2B4: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leukoencephalopathy with vanishing white matter, MIM#603896; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.153 EIF2B3 Zornitza Stark Phenotypes for gene: EIF2B3 were changed from to Leukoencephalopathy with vanishing white matter, MIM#603896
Intellectual disability syndromic and non-syndromic v0.150 EIF2B3 Zornitza Stark reviewed gene: EIF2B3: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leukoencephalopathy with vanishing white matter, MIM#603896; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.150 EIF2B2 Zornitza Stark Phenotypes for gene: EIF2B2 were changed from to Leukoencephalopathy with vanishing white matter, MIM#603896
Intellectual disability syndromic and non-syndromic v0.147 EIF2B2 Zornitza Stark reviewed gene: EIF2B2: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leukoencephalopathy with vanishing white matter, MIM#603896; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.147 EIF2B1 Zornitza Stark Phenotypes for gene: EIF2B1 were changed from to Leukoencephalopathy with vanishing white matter, MIM#603896
Intellectual disability syndromic and non-syndromic v0.144 EIF2B1 Zornitza Stark reviewed gene: EIF2B1: Rating: RED; Mode of pathogenicity: None; Publications: ; Phenotypes: Leukoencephalopathy with vanishing white matter, MIM#603896; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.108 DNM1L Zornitza Stark Phenotypes for gene: DNM1L were changed from to Encephalopathy, lethal, due to defective mitochondrial peroxisomal fission 1, MIM#614388
Intellectual disability syndromic and non-syndromic v0.106 DNM1L Zornitza Stark reviewed gene: DNM1L: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Encephalopathy, lethal, due to defective mitochondrial peroxisomal fission 1, MIM#614388; Mode of inheritance: BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.94 DISP1 Zornitza Stark Phenotypes for gene: DISP1 were changed from to Holoprosencephaly
Intellectual disability syndromic and non-syndromic v0.91 DISP1 Zornitza Stark reviewed gene: DISP1: Rating: RED; Mode of pathogenicity: None; Publications: 19184110, 26748417, 23542665; Phenotypes: Holoprosencephaly; Mode of inheritance: Other
Intellectual disability syndromic and non-syndromic v0.76 CUX2 Zornitza Stark Phenotypes for gene: CUX2 were changed from to Epileptic encephalopathy, early infantile, 67, MIM#618141
Intellectual disability syndromic and non-syndromic v0.73 CUX2 Zornitza Stark reviewed gene: CUX2: Rating: GREEN; Mode of pathogenicity: None; Publications: 29630738, 29795476; Phenotypes: Epileptic encephalopathy, early infantile, 67, MIM#618141; Mode of inheritance: MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Intellectual disability syndromic and non-syndromic v0.69 CTU2 Zornitza Stark gene: CTU2 was added
gene: CTU2 was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert list
Mode of inheritance for gene: CTU2 was set to BIALLELIC, autosomal or pseudoautosomal
Publications for gene: CTU2 were set to 27480277; 26633546
Phenotypes for gene: CTU2 were set to Microcephaly, facial dysmorphism, renal agenesis, and ambiguous genitalia syndrome, MIM#618142
Review for gene: CTU2 was set to GREEN
Added comment: Multiple Saudi families reported with same homozygous variant; founder effect. Severe disorder of infancy.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.21 CNTNAP1 Zornitza Stark Phenotypes for gene: CNTNAP1 were changed from to Hypomyelinating neuropathy, congenital, 3, MIM#618186; Lethal congenital contracture syndrome 7, MIM# 616286
Intellectual disability syndromic and non-syndromic v0.18 CNTNAP1 Zornitza Stark reviewed gene: CNTNAP1: Rating: GREEN; Mode of pathogenicity: None; Publications: 28374019, 29511323, 27668699; Phenotypes: Hypomyelinating neuropathy, congenital, 3, MIM#618186, Lethal congenital contracture syndrome 7, MIM# 616286; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.12 AAAS Zornitza Stark Phenotypes for gene: AAAS were changed from to Achalasia-addisonianism-alacrimia syndrome, MIM#231550
Intellectual disability syndromic and non-syndromic v0.10 CLCN2 Zornitza Stark reviewed gene: CLCN2: Rating: AMBER; Mode of pathogenicity: None; Publications: 23707145; Phenotypes: Leukoencephalopathy with ataxia, MIM#615651; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.6 CDK6 Zornitza Stark reviewed gene: CDK6: Rating: AMBER; Mode of pathogenicity: None; Publications: 23918663; Phenotypes: Microcephaly 12, primary, autosomal recessive, MIM#616080; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Intellectual disability syndromic and non-syndromic v0.6 CACNA1E Zornitza Stark gene: CACNA1E was added
gene: CACNA1E was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert list
Mode of inheritance for gene: CACNA1E was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Publications for gene: CACNA1E were set to 30343943
Phenotypes for gene: CACNA1E were set to Epileptic encephalopathy, early infantile, 69, MIM#618285
Review for gene: CACNA1E was set to GREEN
gene: CACNA1E was marked as current diagnostic
Added comment: At least 30 unrelated patients reported with heterozygous variants in this gene; primarily a seizure disorder, often with profound intellectual disability.
Sources: Expert list
Intellectual disability syndromic and non-syndromic v0.0 AAAS Zornitza Stark reviewed gene: AAAS: Rating: GREEN; Mode of pathogenicity: None; Publications: ; Phenotypes: Achalasia-addisonianism-alacrimia syndrome, MIM#231550; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal; Current diagnostic: yes
Intellectual disability syndromic and non-syndromic v0.0 HAL Zornitza Stark gene: HAL was added
gene: HAL was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert Review Green,Genetic Health Queensland
Mode of inheritance for gene: HAL was set to Unknown