Furthermore, several nervous diseases, including SAH, Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and ischemia, were ameliorated with obvious decreases in apoptosis after the administration of HDAC inhibitors (Kukucka et al., 2013; Didonna and Opal, 2015; Shao et al., 2016), which suggests that HDACs play crucial roles in the apoptotic neurons suffering from extreme stimuli. The gene discussed is HDAC9; the disease is Alzheimer disease.