TNXB and Ullrich congenital muscular dystrophy: Collagen VI, which is deficient in two myopathies, i.e., Ullrich congenital muscular dystrophy and Bethlem myopathy, is downregulated, although with conserved organization of the ECM, in as well TNX-null fibroblasts and Tnxb-/- mice [7,34,35].