COL6A3 and Congenital muscular dystrophy, Ullrich type: In particular, ColVI is critical for the proper structure and function of skeletal muscle, and inherited mutations of the COL6A1-COL6A3 genes cause different forms of myopathies in humans, including Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) (for a review, see15).