A series of Chinese patients with desminopathy associated with six novel and one reported mutations in the desmin gene

Abstract

Desminopathy is a hereditary cardiac and skeletal myopathy caused by mutations in the desmin gene. This study summarizes the clinical, myopathological and genetic features of a series of Chinese patients with desminopathy. Thirty-nine cases from five families with autosomal dominant inheritance and two sporadic cases were investigated. The majority of patients presented with mild myopathy and prominent cardiomyopathy. Fifteen of 16 deceased cases died of cardiac causes. Of the 25 patients alive, 24 patients developed cardiac abnormalities with disease progression. Muscle specimens from nine patients were investigated in various morphological examinations. Gene sequencing and cell transfections were performed to determine whether the mutant desmin formed intermediate filaments. Muscle biopsies revealed 5 cases with dystrophy-like patterns and amorphous material deposits; four other cases showed myopathy-like patterns with cytoplasmic bodies or nemaline bodies. Desmin and multiple proteins aggregated in the affected fibres. Six novel mutations and one previously reported mutation in the desmin gene were identified in the patients. All the mutant desmin genes except E457V produced multiple desmin-positive clumps or abnormal solid large aggregates in transfected cells. This study enlarges the spectrum of desmin mutations and geographic distribution of desminopathy. Although many novel mutations were identified in Chinese patients, the main clinical and myopathological findings were similar to those in Caucasian patients. Cardiac conduction abnormalities were prominent and usually appeared later than skeletal myopathy. The myopathology exhibited some heterogeneity among our patients, but the pathological changes were not indicative of the mutation location in the desmin gene.