FXN and Friedreich ataxia: Although iron deposits have been reported in cardiac muscles of Fxn deficiency mice and FRDA patients, iron accumulation in the nervous system has been reported by some (Boddaert et al., 2007; Koeppen et al., 2009) but not by others (Puccio et al., 2001; Simon et al., 2004; Solbach et al., 2014).