For example, suberoylanilide hydroxamic acid (SAHA, a class 1 HDAC inhibitor) and VPA (broad acting) were able to ameliorate memory deficits, suggesting that HDAC inhibitors may have a potential to improve neuronal function and slow the progression or reverse cognitive deficits in aged patients (Reolon et al., 2011; Benito et al., 2015; Zhao et al., 2018). The gene discussed is HDAC9; the disease is Cognitive impairment.