SMN1 and proximal spinal muscular atrophy: In July 2019, the FDA approved onasemnogene abeparvovec-xioi (Zolgensma®), a viral-mediated SMN1 gene replacement therapy, for SMA in children under the age of 2 years, and the EMA approved it in May 2020 for SMA patients who have two or three copies of the SMN2 gene.