A Study of the Natural Course of SURF1 Deficiency

Participant eligibility for the study will be determined during a screening period lasting up to 45 days. In-clinic follow visits will occur over several days every 6 months for 2 years from baseline. Thereafter, annual telephone follow-up contact will be conducted for 2 additional years. Thus, the active study duration for each participant will be up to approximately 2 years and the total duration per participant will be approximately 4 years. The study will be conducted in the United States and select sites outside the United States based on incidence data.