Long Term Follow-Up for RGX-111

This is a prospective, multicenter, long-term observational, follow-up study to evaluate the long-term safety and efficacy of RGX-111 after a single administration. Eligible participants are those who previously participated in a clinical study where they received a single intracisternal (IC) or intraventricular (IVR; also referred to as intracerebroventricular \[ICV\]) infusion of RGX-111. Enrollment of each participant in this study should occur on the same day or after the participant has completed the end of study (EOS) visit or early discontinuation visit (EDV) from a previous (parent) clinical study. Participants will be followed for up to five years after RGX-111 administration (inclusive of the parent study). No treatment will be directed under this observational study. The total study duration for each participant may vary depending on when s/he enrolls in the current study following RGX-111 administration in the parent study.