MAPT and Alzheimer disease: Autopsy studies suggest that the pathological hallmarks of AD are the extracellular senile amyloid plaques formed by the fibrillar β-amyloid (Aβ); intracellular neurofibrillary tangles (NFTs) formed by hyperphosphorylated tau; and spreading neuron and synapse damages in the memory related brain regions, such as hippocampus and cerebral cortex [461,462,463,464].