In particular, we found that a single IV delivery of an optimized SMN1-encoding AAV9 vector (AAV9-SMN1opti) in neonatal SMNΔ7 mice, a mouse model of human SMA (Le et al., 2005), increased life expectancy up to 355 days in mice that normally survive about 13 days (Dominguez et al., 2011). This evidence concerns the gene SMN1 and proximal spinal muscular atrophy.