SMN2 is a paralogous gene on chromosome 5 that produces a fraction of the survival motor neuron (SMN) protein normally generated by SMN1 1. While SMN1 and SMN2 encode nearly identical proteins, they differ by five nucleotides, with a critical C-to-T transition at codon 280 in exon 7 that causes SMN2 to preferentially skip exon 7 during splicing, generating non-functional protein 2. This splicing defect means SMN2 cannot fully compensate for SMN1 loss, which causes spinal muscular atrophy (SMA), an autosomal-recessive neuromuscular disorder 1. SMN2 copy number is the most important phenotypic modifier of SMA severity, with an inverse correlation between gene copy number and clinical severity 3. SMN protein functions in spliceosome assembly and mRNA transport 4. Clinically, SMN2 is therapeutically significant because it remains intact in SMA patients with SMN1 mutations. Three FDA-approved treatments target SMN2: nusinersen and risdiplam enhance full-length SMN production from SMN2 transcripts 56, while emerging base-editing approaches can correct the exon-7 C•G-to-T•A mutation to restore normal SMN2 splicing 7. These therapies are most effective when administered to neonates and young infants.