SMN1 and proximal spinal muscular atrophy: Treatment options currently available for patients with SMA include nusinersen, an intrathecal inject of antisense oligonucleotide targeting SMN2 pre-mRNA, onasemnogene abeparvovec-xioi, a one-time intravenous infusion of AAV9 containing the SMN1 transgene, and risdiplam, a small molecular SMN2 splicing modifier administered orally.