A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome

This is a Phase 1/2, open-label, multiple-dose, study to evaluate the safety, tolerability, and plasma and CSF concentrations of GTX-102 in pediatric participants with AS. The study includes a Loading phase followed by a Maintenance phase. Participants may continue on GTX-102 during the Maintenance phase of the study until GTX-102 is commercially available, intolerable toxicity occurs, the parent/legal guardian withdraws consent, the participant enrolls in another experimental study, or this study is terminated. This study was previously posted by GeneTX Biotherapeutics, LLC and was transferred to Ultragenyx in July 2022.