In contrast, all forms of vitamin B3 consisting of nicotinamide adenine dinucleotide (NAD+) precursors, nicotinamide, nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR), improved the survival, cardiac function and FXN protein levels via epigenetic regulation in FRDA mouse models (34, 35). Here, FXN is linked to Friedreich ataxia.