It has been shown that in the mdx mouse model for DMD, at least 15–20% of the wild-type dystrophin level was effective in preventing exercise-induced muscle damage (Barton-Davis et al., 1999; van Putten et al., 2012; Godfrey et al., 2015), whereas in humans, at least 30–50% of normal was estimated to be sufficient for preventing disease progression based on dystrophin levels in asymptomatic or mildly-symptomatic Becker muscular dystrophy (BMD) patients (Neri et al., 2007; Anthony et al., 2011). Here, DMD is linked to Becker muscular dystrophy.