To investigate the role of HDACs in HttQ111 mice we took a genetic approach, focusing on two Class I HDACs, HDAC2 and HDAC3, due to previous interest in therapeutic targeting of this class of HDACs in HD (Glajch and Sadri-Vakili, 2015) and the relatively high expression levels of these HDACs in the striatum and in neurons (Broide et al., 2007). The gene discussed is HDAC2; the disease is Huntington disease.