We also discuss the role of histone lactylation in Alzheimer’s disease (glycolysis/H4K12la/PKM2 feedback loop), depression (neuronal excitation), neuroinflammation (anti-inflammatory/pro-inflammatory balance of microglia), aging, stroke (infarct volume), and glioblastoma (activation of oncogenes), pointing out the research directions for the future. This evidence concerns the gene PKM and early-onset autosomal dominant Alzheimer disease.