HDAC9 and Alzheimer disease: Administration of β-Hydroxybutyrate (BHB), a specific class I HDAC inhibitor, in the murine model of AD restricted plaque formation by decreasing the NLRP3 inflammasome and BHB level is reported to be lower in the brain parenchyma and red blood cells of AD patients, suggesting the importance of BHB in AD pathology (Shippy et al. 2020).