FXN and Friedreich ataxia: To gain insights into the consequence of frataxin decrease at the level of the FeS clusters in FRDA patients’ cells, we used Electron Paramagnetic Resonance (EPR) spectroscopy to evaluate the content of these cofactors in intact mitochondria from healthy control (same line used for the co-immunoprecipitation experiments) and two FRDA LCLs homozygous for the GAA triplet expansion (that we named FRDA1 and FRDA2).