After the single systemic administration of Cas9 system components, both genomic editing and dystrophin restoration have been shown to persist for at least 18 months in the mdx mice harboring a point mutation in exon 23 and the DMD mouse model with an exon 44 deletion (ΔEx44) mutation [35,43,44], highlighting the durability of CRISPR therapeutics in dystrophic mice. This evidence concerns the gene DMD and Duchenne muscular dystrophy.