FXN and Friedreich ataxia: As His6‐TAT‐FXN1‐210 has been proposed as an exogenous construct to be used as a substitute for the physiological FXN (which is absent or decreased in FRDA patients), another important issue was whether His6‐TAT‐FXN1‐210 was immunogenic, given that replacement therapies are applied for life, and considering that the TAT sequence is a viral‐derived peptide.