SMN2 and proximal spinal muscular atrophy: To determine whether intrinsic effects of SMN deficiency in PC contribute to cerebellar pathology and the SMA phenotype, we established AAV9 vectors for selective expression in PCs of either GFP (AAV9-L7-6-GFP) or human SMN (AAV9-L7-6-SMN) driven by a previously characterized, PC-specific minimal promoter (L7-6)76.