HDAC9 and Huntington disease: HDAC inhibitors (HDACi) have been shown to improve neuronal survival in HD [143,144] and have been suggested as potential treatment options since the SETDB1 Tudor domain interacts with HDAC 1/2 to achieve transcriptional repression, while mHTT itself reduces the activity of histone acetyltransferases, causing histone deacetylation and thus gene repression [145].