MYOD1 and myotonic dystrophy type 1: The MyoD1-induced system established in a short-term culture is promising for DM1 drug screening, and the iMuSC differentiation system, which led to the formation of myotubes with a higher maturity and enabled the detection of SERCA1 splicing defect, which is expected to be useful to predict the clinical efficacies of candidate drugs.