A number of research groups are also currently screening for novel frataxin-increasing compounds and one group has identified a novel HDAC inhibitor, designated C5, which upregulates FXN expression in FRDA patient primary lymphocytes and increases H3K9ac and H4K8ac in FRDA lymphoblasts (Lufino et al., 2013) (Table 2). This evidence concerns the gene HDAC9 and Friedreich ataxia.