MAPT and Alzheimer disease: SAMe deficiency increases the expression of genes involved in the onset and progression of AD, leading to increased Aβ production (13–16); compromises acetylcholine production and retention in the brain (17); impairs phosphatase function, resulting in accumulation of hyperphosphorylated tau (18); and hinders glutathione-driven quenching of reactive oxygen species (19) promoting a neuroinflammatory state.