MAPT and Alzheimer disease: Anatomically, AD is associated with two types of major lesions: (1) amyloid or senile plaques formed by the extracellular aggregation of insoluble Aβ peptide fibrils and (2) the phosphorylation and destabilization of tau (tubulin-associated unit), a microtubule-associated protein whose aggregation forms neurofibrillary tangles (NFTs) within neurons [21,25,29,30].