Furthermore, the systemic delivery of MyoAAV 2A or AAV9 carrying a micro-dystrophin transgene (CK8-microdystrophin-FLAG) into the DBA/2J-mdx mouse model of DMD using a low dose (2 × 1013 vg/kg) of each AAV was also carried out to estimate the therapeutic efficiency, a quantitative RT-PCR indicated 7.6–15 times higher levels of micro-dystrophin mRNA in skeletal muscles of mice injected with MyoAAV 2A as compared to AAV9. This evidence concerns the gene DMD and Duchenne muscular dystrophy.