Mutations in the genes encoding COLVI (COL6A1, COL6A2, and COL6A3) cause the COLVI-related myopathies, which comprise two major clinical forms, Bethlem myopathy (BM [MIM 158810]) and Ullrich congenital muscular dystrophy (UCMD [MIM 254090]), and the limb girdle and the Myosclerosis myopathy (MM) variants. The gene discussed is COL6A3; the disease is myopathy.