Homozygosity of the Dominant Myotilin c.179C>T (p.Ser60Phe) Mutation Causes a More Severe and Proximal Muscular Dystrophy.

Most myotilinopathy patients present with a dominant late onset distal phenotype and myofibrillar pathology, although the first MYOT mutation in a family reported to have LGMD phenotype. We report here a French family affected with a late onset proximal and distal muscle weakness and myofibrillar myopathy on muscle pathology, in which the siblings known to be clinically affected were homozygous for the c.179C>T (p.Ser60Phe) myotilin gene mutation. One subjectively asymptomatic member of the family was heterozygous for this mutation. This is the first report of a family with patients being homozygous for a known dominant MYOT mutation. Dominant negative mutations are generally considered not to cause a more severe disease in homozygosity, but our data clearly demonstrate the existence of dominant MYOT mutations with a possible dose effect causing a more severe disease phenotype in homozygosity in the spectrum of myofibrillar myopathies (MFM).

Citation

Gabrielle Rudolf, Tiina Suominen, Sini Penttilä, Peter Hackman, Anni Evilä, Béatrice Lannes, Andoni Echaniz-Laguna, Guillaume Bierry, Christine Tranchant, Bjarne Udd. Homozygosity of the Dominant Myotilin c.179C>T (p.Ser60Phe) Mutation Causes a More Severe and Proximal Muscular Dystrophy. Journal of neuromuscular diseases. 2016 May 27;3(2):275-281

PMID: 27854214

search → result