FXN and Friedreich ataxia: Recently, the class III HDAC inhibitor nicotinamide (Ghosh and Feany, 2004) has been shown to increase frataxin expression and decrease H3K9me3 and H3K27me3 at the FXN gene in FRDA cells and mouse models and this compound is now in early stage clinical trials (Chan et al., 2013) (Table 2).