Accumulating evidences have shown that HDAC inhibitors have potential therapeutic roles and can restore memory function in several AD mouse models with amyloid deposition (Francis et al., 2009; Ricobaraza et al., 2009; Kilgore et al., 2010; Govindarajan et al., 2011; Sung et al., 2013). The gene discussed is HDAC9; the disease is Alzheimer disease.