COL6A1 and Congenital muscular dystrophy, Ullrich type: To elucidate whether the supplementation of COL6 is indispensable for the improvement of muscle regeneration and maturation in UCMD model mice, COL6A1 knockout iPSCs were created using the CRISPR-Cas9 System (Figure S1) and differentiated into KO-iMSCs.