MAPT and Alzheimer disease: Histone deacetylases (HDACs) are epigenetic regulators that modulate gene expression by removing acetyl groups from lysine residues on proteins, affecting processes like cell proliferation, differentiation, and development.504,505 Among them, HDAC6 has two catalytic domains and a C-terminal zinc finger domain, interacts with tau and α-tubulin, and is involved in the degradation of protein aggregates, mitochondrial transport, and cognitive memory,506–509 making it relevant to AD pathology.