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| 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 v0.5052 | FEM1C |
Paul De Fazio gene: FEM1C was added gene: FEM1C was added to Intellectual disability syndromic and non-syndromic. Sources: Literature Mode of inheritance for gene: FEM1C was set to MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown Publications for gene: FEM1C were set to 36336956; 28135719; 33398170; 33398168 Phenotypes for gene: FEM1C were set to Neurodevelopmental disorder, FEM1C-related MONDO:0700092 Review for gene: FEM1C was set to GREEN gene: FEM1C was marked as current diagnostic Added comment: PMID:36336956 describes a 9-year-old boy with severe DD, lack of speech, pyramidal signs, and limb ataxia who had a de novo missense variant Asp126His in FEM1C ascertained by WES. The equivalent variant introduced into the nematode C.elegans resulted in disabled locomotion caused by synaptic abnormalities and not muscle dysfunction. An alternate change Asp126Val was reported in the DDD study de novo in a patient with uncharacterised developmental delay (PMID:28135719). The Asp126 residue (but not either of the variants above specifically) was shown to be functionally important by in vitro studies (PMID:33398170;33398168). The residue is highly conserved and located in a region of missense constraint. Borderline green, 2 patients and an animal model. Note all evidence points to the Asp126 residue being of specific importance. Sources: Literature |
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| Intellectual disability syndromic and non-syndromic v0.4997 | FGF14 | Zornitza Stark Phenotypes for gene: FGF14 were changed from to Spinocerebellar ataxia 27, MIM# 609307; Vestibulocerebellar disorder with predominant ocular signs, MIM# 193003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability syndromic and non-syndromic v0.4995 | FGF14 | Zornitza Stark edited their review of gene: FGF14: Changed phenotypes: Spinocerebellar ataxia 27, MIM# 609307, Vestibulocerebellar disorder with predominant ocular signs, MIM# 193003 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability syndromic and non-syndromic v0.4939 | PTPA |
Konstantinos Varvagiannis changed review comment from: Biallelic PTPA pathogenic variants lead to a form of ID with later-onset parkinsonism based on 4 individuals from 2 families in the literature. Affected individuals were homozygous for missense variants demonstrated to result to reduced mRNA and protein levels as well as PP2A complex activation. Drosophila studies support an age-dependent locomotor dysfunction. Variants in other PP2A-complex-related genes also lead to NDDs. Summary provided below. There is currently no associated phenotype in OMIM, G2P, PanelApp Australia or SysID. Consider inclusion in relevant panels (ID, Parkinsonism/movement disorders, etc) with amber rating pending further reports. ------ Fevga, Tesson et al (2022 - PMID: 36073231) describe the features of 4 individuals, from 2 unrelated families, with biallelic pathogenic PTPA variants. These presented with normal or delayed early milestones, learning disability and ID (mild to moderate) followed by progressive signs of parkinsonism (at the age of 11 yrs in 2 sibs, 15 yrs in another individual). Motor symptoms were responsive to levodopa and later to deep brain stimulation. Linkage analysis in one consanguineous family followed by exome revealed homozygosity for a missense PTPA variant (NM_178001:c.893T>G/p.Met298Arg). Exome sequencing in affected subjects from the 2nd family revealed homozygosity for a further missense variant (c.512C>A/p.Ala171Asp). There were no other candidate variants for the phenotype following parental / segregation studies. Role of the gene: As the authors discuss, PTPA (or PPP2R4) is ubiquitously expressed in all tissues incl. brain and encodes a phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase-2A (PP2A). PP2A in turn, is the major Ser/Thr phosphatase in brain targeting a large number of proteins involved in diverse functions. Activation of PP2A is dependent on its methylation, which is negatively regulated by the PP2A-specific methylesterase (PME-1). By binding to PME-1, PTPA counteracts the negative influence of the former on PP2A. Pathogenic variants in genes encoding subunits/regulators of the PP2A complex (e.g. PPP2R1A or PPP2CA) are associated with neurodevelopmental disorders. Variant studies: Upon overexpression of wt and both variants in a HEK-293 cell line the authors demonstrated that both variants resulted in significantly reduced mRNA and protein levels (which for Ala171Asp were attributed to increased proteasomal degradation). Both variants were shown to result in impaired PP2A complex activation compared to wt. Drosophila / animal models: Pan-neuronal RNAi-mediated knockdown of ptpa in Drosophila resulted in an age-dependent locomotor dysfunction, reversible with L-DOPA treatment. Previous studies in mice suggest cognitive/electrophysiological impairments upon downregulation of PP2A activity in transgenic mice. Sources: Literature; to: Biallelic PTPA pathogenic variants lead to a form of ID with later-onset parkinsonism based on 4 individuals from 2 families in the literature. Affected individuals were homozygous for missense variants demonstrated to result to reduced mRNA and protein levels as well as PP2A complex activation. Drosophila studies support an age-dependent locomotor dysfunction. Variants in other PP2A-complex-related genes also lead to NDDs. Summary provided below. There is currently no associated phenotype in OMIM, G2P, PanelApp UK or SysID. Consider inclusion in relevant panels (ID, Parkinsonism/movement disorders, etc) with amber rating pending further reports. ------ Fevga, Tesson et al (2022 - PMID: 36073231) describe the features of 4 individuals, from 2 unrelated families, with biallelic pathogenic PTPA variants. These presented with normal or delayed early milestones, learning disability and ID (mild to moderate) followed by progressive signs of parkinsonism (at the age of 11 yrs in 2 sibs, 15 yrs in another individual). Motor symptoms were responsive to levodopa and later to deep brain stimulation. Linkage analysis in one consanguineous family followed by exome revealed homozygosity for a missense PTPA variant (NM_178001:c.893T>G/p.Met298Arg). Exome sequencing in affected subjects from the 2nd family revealed homozygosity for a further missense variant (c.512C>A/p.Ala171Asp). There were no other candidate variants for the phenotype following parental / segregation studies. Role of the gene: As the authors discuss, PTPA (or PPP2R4) is ubiquitously expressed in all tissues incl. brain and encodes a phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase-2A (PP2A). PP2A in turn, is the major Ser/Thr phosphatase in brain targeting a large number of proteins involved in diverse functions. Activation of PP2A is dependent on its methylation, which is negatively regulated by the PP2A-specific methylesterase (PME-1). By binding to PME-1, PTPA counteracts the negative influence of the former on PP2A. Pathogenic variants in genes encoding subunits/regulators of the PP2A complex (e.g. PPP2R1A or PPP2CA) are associated with neurodevelopmental disorders. Variant studies: Upon overexpression of wt and both variants in a HEK-293 cell line the authors demonstrated that both variants resulted in significantly reduced mRNA and protein levels (which for Ala171Asp were attributed to increased proteasomal degradation). Both variants were shown to result in impaired PP2A complex activation compared to wt. Drosophila / animal models: Pan-neuronal RNAi-mediated knockdown of ptpa in Drosophila resulted in an age-dependent locomotor dysfunction, reversible with L-DOPA treatment. Previous studies in mice suggest cognitive/electrophysiological impairments upon downregulation of PP2A activity in transgenic mice. Sources: Literature |
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| Intellectual disability syndromic and non-syndromic v0.4939 | PTPA |
Konstantinos Varvagiannis gene: PTPA was added gene: PTPA was added to Intellectual disability syndromic and non-syndromic. Sources: Literature Mode of inheritance for gene: PTPA was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: PTPA were set to 36073231 Phenotypes for gene: PTPA were set to Intellectual disability; Parkinsonism Penetrance for gene: PTPA were set to Complete Review for gene: PTPA was set to AMBER Added comment: Biallelic PTPA pathogenic variants lead to a form of ID with later-onset parkinsonism based on 4 individuals from 2 families in the literature. Affected individuals were homozygous for missense variants demonstrated to result to reduced mRNA and protein levels as well as PP2A complex activation. Drosophila studies support an age-dependent locomotor dysfunction. Variants in other PP2A-complex-related genes also lead to NDDs. Summary provided below. There is currently no associated phenotype in OMIM, G2P, PanelApp Australia or SysID. Consider inclusion in relevant panels (ID, Parkinsonism/movement disorders, etc) with amber rating pending further reports. ------ Fevga, Tesson et al (2022 - PMID: 36073231) describe the features of 4 individuals, from 2 unrelated families, with biallelic pathogenic PTPA variants. These presented with normal or delayed early milestones, learning disability and ID (mild to moderate) followed by progressive signs of parkinsonism (at the age of 11 yrs in 2 sibs, 15 yrs in another individual). Motor symptoms were responsive to levodopa and later to deep brain stimulation. Linkage analysis in one consanguineous family followed by exome revealed homozygosity for a missense PTPA variant (NM_178001:c.893T>G/p.Met298Arg). Exome sequencing in affected subjects from the 2nd family revealed homozygosity for a further missense variant (c.512C>A/p.Ala171Asp). There were no other candidate variants for the phenotype following parental / segregation studies. Role of the gene: As the authors discuss, PTPA (or PPP2R4) is ubiquitously expressed in all tissues incl. brain and encodes a phosphotyrosyl phosphatase activator of the dimeric form of protein phosphatase-2A (PP2A). PP2A in turn, is the major Ser/Thr phosphatase in brain targeting a large number of proteins involved in diverse functions. Activation of PP2A is dependent on its methylation, which is negatively regulated by the PP2A-specific methylesterase (PME-1). By binding to PME-1, PTPA counteracts the negative influence of the former on PP2A. Pathogenic variants in genes encoding subunits/regulators of the PP2A complex (e.g. PPP2R1A or PPP2CA) are associated with neurodevelopmental disorders. Variant studies: Upon overexpression of wt and both variants in a HEK-293 cell line the authors demonstrated that both variants resulted in significantly reduced mRNA and protein levels (which for Ala171Asp were attributed to increased proteasomal degradation). Both variants were shown to result in impaired PP2A complex activation compared to wt. Drosophila / animal models: Pan-neuronal RNAi-mediated knockdown of ptpa in Drosophila resulted in an age-dependent locomotor dysfunction, reversible with L-DOPA treatment. Previous studies in mice suggest cognitive/electrophysiological impairments upon downregulation of PP2A activity in transgenic mice. Sources: Literature |
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| Intellectual disability syndromic and non-syndromic v0.4876 | SMG9 | Zornitza Stark Phenotypes for gene: SMG9 were changed from Heart and brain malformation syndrome, MIM# 616920 to Heart and brain malformation syndrome, MIM# 616920; Neurodevelopmental disorder with intention tremor, pyramidal signs, dyspraxia, and ocular anomalies, MIM# 619995 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability syndromic and non-syndromic v0.4874 | SMG9 | Zornitza Stark edited their review of gene: SMG9: Added comment: PMID 35087184: 5 individuals from 3 unrelated Finnish families reported with same homozygous missense variant (founder effect) and predominantly neurological phenotype. Uncertain if this is a distinct disorder or part of a spectrum with the previously reported cases.; Changed publications: 27018474, 31390136, 35087184; Changed phenotypes: Heart and brain malformation syndrome, MIM# 616920, Neurodevelopmental disorder with intention tremor, pyramidal signs, dyspraxia, and ocular anomalies, MIM# 619995 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability syndromic and non-syndromic v0.4233 | SPRED2 |
Dean Phelan gene: SPRED2 was added gene: SPRED2 was added to Intellectual disability syndromic and non-syndromic. Sources: Literature Mode of inheritance for gene: SPRED2 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: SPRED2 were set to PMID: 34626534 Phenotypes for gene: SPRED2 were set to developmental delay; intellectual disability; cardiac defects; short stature; skeletal anomalies; a typical facial gestalt Review for gene: SPRED2 was set to GREEN Added comment: PMID: 34626534 Homozygosity for three different variants c.187C>T (p.Arg63∗), c.299T>C (p.Leu100Pro), and c.1142_1143delTT (p.Leu381Hisfs∗95) were identified in four subjects from three families. All variants severely affected protein stability, causing accelerated degradation, and variably perturbed SPRED2 functional behaviour. The clinical phenotype of the four affected individuals included developmental delay, intellectual disability, cardiac defects, short stature, skeletal anomalies, and a typical facial gestalt as major features, without the occurrence of the distinctive skin signs characterizing Legius syndrome. Sources: Literature |
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| Intellectual disability syndromic and non-syndromic v0.3543 | DM1 |
Bryony Thompson STR: DM1 was added STR: DM1 was added to Intellectual disability syndromic and non-syndromic. Sources: Expert list Mode of inheritance for STR: DM1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for STR: DM1 were set to 20301344; 29325606 Phenotypes for STR: DM1 were set to Myotonic dystrophy 1 MIM#160900 Review for STR: DM1 was set to GREEN STR: DM1 was marked as clinically relevant Added comment: HGVS nomenclature: NM_001081560.2:c.*224_*226CTG[X] RNA toxic gain of function is mechanism of disease Premutation: 35-49 repeats, no clinical signs Mild: 50-~150 repeats, age of onset 20-70 yrs, clinical signs - cataracts, mild myotonia Classic: ~100-~1,000 repeats, age of onset 10-30 yrs, clinical signs - weakness, myotonia, cataracts, balding, cardiac arrhythmia Congenital: >1,000 repeats, age of onset birth-10 yrs , clinical signs - infantile hypotonia, respiratory deficits, intellectual disability, classic signs in adults Sources: Expert list |
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| 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 v0.3078 | MICU1 | Zornitza Stark Phenotypes for gene: MICU1 were changed from to Myopathy with extrapyramidal signs, MIM# 615673 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Intellectual disability syndromic and non-syndromic v0.3075 | MICU1 | Zornitza Stark reviewed gene: MICU1: Rating: GREEN; Mode of pathogenicity: None; Publications: 24336167, 29721912, 32395406; Phenotypes: Myopathy with extrapyramidal signs, MIM# 615673; Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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. |
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| Intellectual disability syndromic and non-syndromic v0.0 | GNS |
Zornitza Stark gene: GNS was added gene: GNS was added to Intellectual disability, syndromic and non-syndromic_GHQ. Sources: Expert Review Green,Genetic Health Queensland Mode of inheritance for gene: GNS was set to Unknown |
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