Molecular-genetic characteristics of Facioscapulohumeral muscular dystrophy in the Russian population

Abstract

Facioscapulohumeral dystrophy (FSHD) is an autosomal dominant myodystrophy. In approximately 95% of cases FSHD is caused by partial deletion of the D4Z4 macrosatellite tandem repeat on chromosome 4q35 (FSHD1). Here we present results FSHD1 diagnostic of patients and unaffected relatives from Russian population. We demonstrate that FSHD1 permissive alleles are bigger in size for unaffected carriers, which indicate previously reported phenomenon of inverse correlation between permissive allele size and disease penetrance and expressivity. In addition, presence of patients and unaffected carriers from one family with the same permissive allele size demonstrate importance of non-genetic factors for disease development.