The former approach includes the antisense-oligonucleotide drug nusinersen, which rescues deficient SMN2 exon 7 inclusion for spinal muscular atrophy therapy1–3, and small-molecule compounds, such as SMN-C3 and RG7916, that also promote SMN2 exon 7 inclusion, in part by directly binding to an imperfect RNA helix formed by the exon 7 5′-splice site and U1 snRNA acting for bulge repair4–8. This evidence concerns the gene SMN2 and proximal spinal muscular atrophy.