Researchers at the Créteil Neuromuscular Reference Centre (Henri-Mondor University Hospital) report the observation of a 36-year-old patient with a congenital onset of titinopathy:
- initial hypotonia and arthrogryposis developed into a highly retractile syndrome,
- muscle biopsy revealed increased internalisation of cell nuclei, variation in fibre size and predominance of type I fibres,
- genetic studies revealed the presence of a homozygous variant of the TTN gene encoding titin, resulting in a mutation of a metatranscript with retention of introns 170 and 171,
- functional studies have made it possible to incriminate muscular hypotrophy itself, and not the sarcomere, in the genesis of the motor deficit.
This work provides a better understanding of the phenotypic range of early-onset titinopathies and proves the existence of cases with prolonged survival.
