A Single-Stage, Adaptive, Open-label, Dose Escalation Safety and Efficacy Study of AADC Deficiency in Pediatric Patients

Initially, subjects will be enrolled sequentially into 2 dose groups. 3 subjects will be enrolled in Cohort 1 and treated with a single dose of AAV2 hAADC (1.3x10 11 vg, delivered as infusate volume of up to 160μL of vector at concentration of 8.3x10 11 vg/mL) on Day 0. Enrollment in Cohort 2 may commence after the last subject in Cohort 1 is treated and followed through Month 3 post-op, with approval of the data safety monitoring board (DSMB). Cohort 2 will receive a higher dose (4.2 x 10\^11 vg, 160 uL). Upon DSMB review of Cohort 1/2 results, Cohort 3 (4-12 yo) and 4 (aged \>/= 13 yo) will be dosed (1.6 x 10\^12 vg, 60uL) in 1-2 sites bilaterally in-between the SNc and VTA. Cohort 5 will follow (aged 24-47 months) at 1.3 x 10\^12 vg, 500uL. Final safety and clinical outcome assessments will be performed 1 year post-surgery. Follow-up analysis will be performed for 2 years post-op. Subjects will be enrolled in a long-term follow-up study to assess safety and clinical status updates.