1. Has a genetically-confirmed diagnosis (homozygous for guanine-adenine-adenine [GAA] repeat expansions in the frataxin gene [FXN] in the affected range of Friedreich ataxia [FRDA] or a compound heterozygous expansion with a point mutation or deletion), with an established disease stage of 2 to 5, inclusive, as determined by the Functional Staging for Ataxia, at Screening.