Accordingly, three FDA approved therapies are used for treating SMA patients, based either on antisense oligonucleotides (ASOs; Nusinersen/Spinraza) or small molecules (Evrysdi/Risdiplam) that improve exon7 splicing of SMN2-derived transcripts (Finkel et al., 2016; Mercuri et al., 2018; Ratni et al., 2018), or on SMN1 gene replacement using AAV9 (Zolgensma/Onasmnogene abeparvovec; Mendell et al., 2017). This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.