In FRDA, the HDAC inhibitors 109/RG2833 and nicotinamide (vitamin B3) have shown the most promising results in restoring frataxin to normal levels by increasing histone acetylation at the FXN locus (Nageshwaran and Festenstein, 2015; Burk, 2017). The gene discussed is HDAC9; the disease is Friedreich ataxia.