Severe myoclonus-dystonia syndrome associated with a novel epsilon-sarcoglycan gene truncating mutation.

Myoclonus-dystonia syndrome (MDS) is an autosomal dominant disorder characterized by myoclonic and dystonic muscle contractions, associated with psychiatric manifestations. MDS is usually considered as a benign disease. In most of the families, MDS is linked to chromosome 7q21 and mutations within epsilon-sarcoglycan (SGCE) gene have been recently described. We report a MDS family with a severe and heterogeneous phenotype, including myoclonus with important functional impact and several psychiatric features, characterized by obsessive-compulsive disorder, depression, and anxiety. This phenotype was shown to be associated with a novel truncating mutation located within exon 4 of SGCE.