SMN2 and proximal spinal muscular atrophy: Various clinical SMA drug has been approved recent years by the Food and Drug Administration (FDA), such as antisense oligo nucleotides (ASOs) drug Nusinersen (Spinraza) by correction of SMN2 exon 7 splicing, gene therapy targeting SMN1 using AAV [31], and an orally deliverable small molecule drug-risdiplam (Evrysdi) that the therapeutic effect would be able to reach to all organs [32].