In this FRDA cohort, the average lengths of the GAA tracts are 454 and 898 repeats for FXN alleles 1 and 2 (GAA1 and GAA2), respectively (Table S1), whereas the number of GAA triplets did not exceed 40 repeats in any of the CTRL fibroblast lines (Li et al., 2015b). Here, FXN is linked to Friedreich ataxia.