The conditional frataxin-KO models, which exhibit severe early-onset FRDA-like pathologies, have been extremely useful for assessing potential FRDA drug therapies acting on the downstream effects of frataxin deficiency, including antioxidants and iron chelators (Seznec et al., 2004; Whitnall et al., 2008), and more recently for FRDA gene therapy (Perdomini et al., 2014). The gene discussed is FXN; the disease is Friedreich ataxia.