DMD and muscular disease: For example, in exploring treatment for Duchenne muscular dystrophy (DMD), a muscle disorder caused by mutations in the DMD gene, researchers used CRISPR/Cas9 in patient-derived cells and mouse models to delete the exons from the mutated DMD gene to restore a normal reading frame to correct different mutations in DMD genes [16,17], which has been reviewed in more detail elsewhere [18,19].