MAPT and Alzheimer disease: The buildup of β-amyloid protein and intracellular aggregation of tau protein are the noxious etiological agents, which might trigger synaptopathies, glial inflammation, and eventual neuronal death in the cerebral cortex, sub-cortical regions, temporal and parietal lobes, and cingulate gyrus, observed in AD [30,31,32,33,34,35].