In our study, to evaluate if the specific HDAC inhibitor RGFP109 could alleviate the transcriptional dysregulation in HD in vivo and improve the characteristic neuroanatomical HD features and behavioral deficits, we treated R6/1 mice (11–14 weeks of age) with 30 mg/kg (i.p.)RGFP109 five times a week for 3 weeks (total of 23 days) (Figure 1A). Here, HDAC9 is linked to Huntington disease.