Targeted genome editing in vivo corrects a Dmd duplication restoring wild-type dystrophin expression


Many rare inheritable diseases often result from duplication mutations. Unfortunately, there is difficulty finding animal models that accurately represent these types of mutations and thus limit the development of therapies for patients suffering from these disorders, including Duchenne Muscular Dystrophy (DMD). In this paper, a novel multi-exonic duplication of the Dmd gene was created in a mouse model (Dup18-30). These mice displayed altered muscle histopathology and phenotypes characteristic of DMD. The authors set out to correct this mutation in-vivo using a unique single-sgRNA/CRISPR Cas9 technique. Following treatment, this duplication mutation was eliminated in both cardiac and skeletal muscle tissue. Further investigation revealed expression of full-length dystrophin was restored and resulted in enhanced muscle tissue architecture and phenotype improvements. In-vivo muscle mechanics were performed using Aurora’s 1300A 3-in-1 Whole Animal System which indicated a functional improvement in hindlimb muscles. These results lay the foundation for future therapies targeting diseases that are the result of duplication mutations, including DMD.