Congenital muscular dystrophy with glycosylation defects of alpha-dystroglycan in Japan.

Glycosylation defects of alpha-dystroglycan (alpha-DG) cause various muscular dystrophies. We performed clinical, pathological and genetic analyses of 62 Japanese patients with congenital muscular dystrophy, whose skeletal muscle showed deficiency of glycosylated form of alpha-DG. We found, the first Japanese patient with congenital muscular dystrophy 1C with a novel compound heterozygous mutation in the fukutin-related protein gene. Fukuyama-type congenital muscular dystrophy was genetically confirmed in 54 of 62 patients. Two patients with muscle-eye-brain disease and one Walker-Warburg syndrome were also genetically confirmed. Four patients had no mutation in any known genes associated with glycosylation of alpha-DG. Interestingly, the molecular mass of alpha-DG in the skeletal muscle was similar and was reduced to approximately 90 kDa among these patients, even though the causative gene and the clinico-pathological severity were different. This result suggests that other factors can modify clinical features of the patients with glycosylation defects of alpha-DG.