Interestingly, some studies have found that the use of HDAC inhibitors can promote the course of Alzheimer’s disease by changing the acetylation status of chromatin and other non-histone proteins, regulating the expression of target genes, inducing neuronal apoptosis and autophagy (Thomas and D’Mello, 2018; Gupta et al., 2020). Here, HDAC9 is linked to Alzheimer disease.