MAPT and Alzheimer disease: Alzheimer’s disease (AD) is the most common neurodegenerative disease that is pathologically characterized by brain β-amyloid (Aβ) deposition forming extracellular plaques, Tau hyperphosphorylation aggregating to intracellular neurofibrillary tangles, and the progressive reduction of synapses and neurons causing brain atrophy (Alzheimer’s Association, 2021).