An autosomal dominant hereditary myopathy with, phenotypically, a very marked tremor in the foreground has recently been described and linked to the MYBPC1 gene encoding a myosin-associated protein C. The authors of this ultra-rare disease report another case, but with a different genotype:
- the patient concerned had mild myopathy but a marked tremor of the extremities,
- high-throughput sequencing (NGS) identified a de novo mutation in the MYH7 gene encoding a myosin heavy chain,
- electroneuromyography showed a distinctive and recognisable profile.
The authors have attempted to provide pathophysiological explanations, but much remains to be understood.