COL6A1 and Congenital muscular dystrophy, Ullrich type: Mutations in COL6A1 have been reported to cause, among others, Bethlem myopathy (omim.org/entry/158810) and Ullrich Congenital Muscular Dystrophy 1 (omim.org/entry/254090) characterized by increased skeletal muscle weakness and joint stiffness in infancy.