Of note, pre-clinical studies with ΔR4-R23/ΔCT micro-dystrophin (abbreviated as ‘μDys’ in this manuscript), a micro-dystrophin currently in a phase 1/2a clinical trial (5,14), showed incomplete rescue of cardiac function in the mdx mouse model of DMD (15–17). The gene discussed is DMD; the disease is Duchenne muscular dystrophy.