Arthrogryposis

Gene: TNNI1

I don't know

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: Literature

Created: 7 Apr 2022, 1:28 a.m.

Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Phenotypes
arthrogryposis; joint contractures

Publications

• 34934811