FXN and Friedreich ataxia: Loss of yeast frataxin homolog results in iron accumulation (Babcock et al., 1997), and this phenotype has also been reported in cardiac muscles of a Fxn deficiency mouse and FRDA patients (Koeppen, 2011; Lamarche et al., 1980; Michael et al., 2006; Puccio et al., 2001).