Mutations in the genes encoding collagen VI (COL6A1, COL6A2 and COL6A3) result in two major phenotypes: Bethlem myopathy [BM, OMIM #158810] and Ullrich congenital muscular dystrophy [UCMD, OMIM #254090]. Here, COL6A3 is linked to Ullrich congenital muscular dystrophy.