FXN and Friedreich ataxia: Due to the ubiquitous nature of the frataxin expression, FA is a multisystemic disease where, despite the death of dorsal root ganglia (DRG) neurons and cardiomyopathy, which represent, respectively, the first pathologic event and the primary cause of death [21,146], patients also display a number of secondary defects including diabetes, hearing loss, visual impairments, and cognitive deficits [146].