AVXS-101-CL-101 (ClinicalTrials.gov identifier: NCT02122952, years 2014–2017) is an open-label study of 15 SMA type I cases with bi-allelic SMN1 mutations (deletion or point mutations) and two copies of SMN2. Onasemnogene abeparvovec was administered as a single intravenous injection at two different doses: Twelve patients receiving 2.0 × 1014 vector genomes (vg) per kg and three receiving 6.7 × 1013 vg per kg. This evidence concerns the gene SMN1 and spinal muscular atrophy, type 1.