The presence of granular iron deposits in the mitochondria of cardiomyocytes was one of the first findings of iron metabolism dysregulation in FRDA patients (Sanchez-Casis et al., 1976; Lamarche et al., 1980; Martelli and Puccio, 2014), which very quickly led to the suspicion that frataxin could function as an iron storage protein (Adamec et al., 2000; Cossee et al., 2000; Gakh et al., 2002). Here, FXN is linked to Friedreich ataxia.