COL6A1 and Ullrich congenital muscular dystrophy: Mutations of COL6 genes (COL6A1, COL6A2, and COL6A3) cause COL6-related myopathies,1 a group of rare inherited muscle diseases that include Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD), as well as the limb girdle and myosclerosis myopathy variants.2,3