Proof of principle has been established in preclinical studies showing that shortened forms of dystrophin (micro-dystrophin) have the potential to ameliorate muscle pathology and cardiomyopathy when delivered in multiple DMD animal models (Gregorevic et al., 2008; Koo et al., 2011; Le Guiner et al., 2017; Liu et al., 2005; Shin et al., 2013; Yue et al., 2003). The gene discussed is DMD; the disease is Duchenne muscular dystrophy.