Indeed, virus-mediated gene therapies have now been approved by the FDA in the US for RPE65-associated retinal dystrophy (voretigene neparvovec marketed as Luxturna) and SMN1-linked spinal muscular atrophy (SMA; onasemnogene abeparvovec marketed as Zolgenmsa), as well as non-neuronal conditions (High and Roncarolo, 2019). This evidence concerns the gene SMN1 and proximal spinal muscular atrophy.