Gene Transfer Clinical Trial for Spinal Muscular Atrophy Type 1

Inclusion Criteria: * Six or nine months of age and younger (depending on cohort) on day of vector infusion with Type 1 SMA as defined by the following features: * Diagnosis of SMA based on gene mutation analysis with bi-allelic SMN1 mutations (deletion or point mutations) and 2 copies of SMN2. * Onset of disease at birth up to 6 months of age. * Hypotonia by clinical evaluation with delay in motor skills, poor head control, round shoulder posture and hypermobility of joints. Exclusion Criteria: * Active viral infection (includes HIV or serology positive for hepatitis B or C) * Use of invasive ventilatory support (tracheotomy with positive pressure)\* or pulse oximetry \<95% saturation. * Patients may be put on non-invasive ventilator support (BiPAP) for less than 16 hours a day at the discretion of their physician or research staff. * Concomitant illness that in the opinion of the PI creates unnecessary risks for gene transfer * Concomitant use of any of the following drugs: drugs for treatment of myopathy or neuropathy, agents used to treat diabetes mellitus, or ongoing immunosuppressive therapy or immunosuppressive therapy within 3 months of starting the trial (e.g. corticosteroids, cyclosporine, tacrolimus, methotrexate, cyclophosphamide, intravenous immunoglobulin, rituximab) * Patients with Anti-AAV9 antibody titers \>1:50 as determined by ELISA binding immunoassay. * Abnormal laboratory values considered clinically significant (GGT \> 3XULN, bilirubin ≥ 3.0 m…