MAPT and Alzheimer disease: The neuropathological hallmarksof AD are the presence of neuritic (senile) plaques (NP) and neurofibrillarytangles (NFT), along with neuronal loss, dystrophic neurites, and gliosis.Neuritic plaques are extracellular lesions and their main constituent is theamyloid-β42 peptide (Aβ42).Neurofibrillary tangles are intracellular lesions that are mainly composed ofhyperphosphorylated Tau protein.