SMN1 and proximal spinal muscular atrophy: Nusinersen, the first approved drug treatment option for SMA is an antisense oligonucleotide that increases SMN protein expression via modification of the splicing process of the pre-mRNA of SMN2.6, –8 Risdiplam is a small molecule and oral medication acting in a similar way.9,10 Onasemnogene abeparvovec-xioi is a gene replacement therapy which comprises an adeno-associated viral vector with the human SMN1 gene.11, , –14