DMD and Duchenne muscular dystrophy: In this study, using immunodeficient NOD-scid-IL2Rg−/− (NSI) mice and DMD patient muscle-derived stem cells (DMD–MDSCs), we developed a patient-derived xenograft (PDX) DMD mouse model to conduct in vivo genome editing via AAV-mediated CRISPR system and restore the expression of dystrophin in DMD patient muscle fibers.