SMN2 and proximal spinal muscular atrophy: The SMA community has witnessed three recent breakthrough gene-targeted treatments for SMA patients: Spinraza (nusinersen), a SMN2-splicing antisense oligonucleotide approved by the US Food and Drug Administration (FDA) in 2016; Zolgensma (onasemnogene abeparvovec), an AAV9-mediated gene replacement therapy in 2019; and Evrysdi (risdiplam), a SMN2 splicing modifier small molecule in 2020 (see recent reviews by [43,44,45]).