RYR1 and Duchenne muscular dystrophy: In summary, our results emphasize the key role of RYR1 in human DMD pathophysiology: (i) RYR1-mediated Ca2+ leakage through SR due to calstabin1 depletion delays skeletal muscle differentiation in DMD, and this can be improved by S107; (ii) the elevated cytosolic Ca2+ concentration is correlated with endomysial fibrosis, suggesting its involvement in DMD prognosis.