SMN1 and proximal spinal muscular atrophy: Importantly, either IV or IM delivery of AAV9 vectors engineered to overexpress the Survival of Motor Neuron gene 1 (SMN1) gene dramatically rescued the pathological phenotype in a mouse model of spinal muscular atrophy (SMA) (Foust et al., 2010; Valori et al., 2010; Dominguez et al., 2011; Benkhelifa-Ziyyat et al., 2013).