MAPT and Alzheimer disease: AD is histopathologically identified by the presence of extracellular amyloid plaques composed of amyloid-beta (Aβ) and intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated Tau proteins in paired helical (PHFs) or straight filaments (SFs) (Crowther, 1991; Bloom, 2014; Götz et al., 2019).