Arthrogryposis
Gene: TNNI1
No OMIM gene disease association reported
PMID 34934811 Nishimori et al report 2 individuals from a Japanese family with joint contractures, elevated CK and a novel heterozygous TNNI1 variant.
The proband was born with clasped thumbs (gestational age not stated) requiring surgical correction at 5 months of age. At age 14 was diagnosed with contractures of the neck, trunk, hip and knee with elevated serum CK (1689 IU/L). No muscle weakness noted. Muscle biopsy showed moth-eaten appearance of type I fibres and electron microscopy showed type 1 fibre Z disk streaming.
Trio exome sequencing identified a paternally heterozygous nonsense TNNI1 variant (c.523A>T p.K175*). The proband's father and paternal grandfather (not genotyped) also have a history of joint contractures with elevated CK.
The affected amino acid residue is in the tropomyosin binding site near the C-terminus and is highly conserved. The variant is absent from gnomAD. rt-PCR products of mRNA from the patient's muscle biopsy showed presence of both mutated and normal transcripts.
Sources: LiteratureCreated: 7 Apr 2022, 1:28 a.m.
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Phenotypes
arthrogryposis; joint contractures
Publications
Gene: tnni1 has been classified as Amber List (Moderate Evidence).
Gene: tnni1 has been classified as Amber List (Moderate Evidence).
Phenotypes for gene: TNNI1 were changed from arthrogryposis; joint contractures to Arthrogryposis MONDO:0008779, TNNI1-related
gene: TNNI1 was added gene: TNNI1 was added to Arthrogryposis. Sources: Literature Mode of inheritance for gene: TNNI1 was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: TNNI1 were set to 34934811 Phenotypes for gene: TNNI1 were set to arthrogryposis; joint contractures Review for gene: TNNI1 was set to AMBER