COL6A3 and Ullrich congenital muscular dystrophy: The collagen-VI-related myopathies, ranging from severe Ullrich congenital muscular dystrophy (UCMD) to mild Bethlem myopathy (BM) and intermediate clinical phenotypes, are caused by mutations in one of the genes that encode the three major α chains of collagen type VI: COL6A1 (MIM*120220), COL6A2 (MIM*120240), and COL6A3 (MIM*120250).2, 3 The severe UCMD is an early-onset CMD variant that presents with slowly progressive muscle weakness, progressive joint contractures, and respiratory failure and the frequent development of severe scoliosis.4