MAPT and Alzheimer disease: Clinically, pathological features of AD are extracellular senile plaques composed of fibrillar amyloid‐β (Aβ) peptides and intracellular neurofibrillary tangles containing hyperphosphorylated tau, accompanied by synaptic dysfunction and neuronal death (Mangialasche, Solomon, Winblad, Mecocci, & Kivipelto, 2010).