HDAC9 and Huntington disease: HDAC inhibition has been shown to ameliorate transcriptional changes in HD and improve behavioral deficits across different experimental models (Steffan et al., 2001; Ferrante et al., 2003, 2004; Hockly et al., 2003; Butler and Bates, 2006; Ryu et al., 2006; Kazantsev and Thompson, 2008; Pallos et al., 2008).