MAPT and Alzheimer disease: The neuropathological hallmarks of AD include severe atrophy of the medial temporal lobes, particularly the hippocampus and entorhinal cortex, and the accumulation of extracellular senile plaques composed of Aβ, together with intracellular neurofibrillary tangles composed of phosphorylated tau (Whitwell, 2010; Tcw and Goate, 2017).