In Canada and Europe, onasemnogene abeparvovec is used for the treatment of pediatric patients with 5q SMA that have bi-allelic mutations in the SMN1 gene, and who are either clinically diagnosed as SMA type 1, or possess three or fewer copies of the SMN2 gene [17,18,32]. The gene discussed is SMN2; the disease is spinal muscular atrophy, type 1.