MAPT and Alzheimer disease: AD is characterized by two neuropathologic hallmarks: (1) extracellular plaques comprised of Amyloid beta (Aβ) fibrils and (2) intraneuronal aggregates of hyperphosphorylated Tau (pTau) that accumulate in neuritic plaques (NPs), neuropil threads (NTs) and neurofibrillary tangles (NFTs) [9, 15].