SMN1 and proximal spinal muscular atrophy: However, we have reached a new therapeutic era for SMA, with the approval and licencing of three genetic therapies: Spinraza® is an antisense oligonucleotide that modulates splicing of SMN2 to increase SMN production [7]; Zolgensma® is a viral vector that introduces a second copy of SMN1 to boost SMN expression [8]; and Evrysdi® is a small molecule that also alters SMN2 splicing [9].