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. The gene discussed is COL6A3; the disease is Ullrich congenital muscular dystrophy.