The main neuropathological hallmark of AD is the aggregation in the brain of two different proteins: (1) β-amyloid (Aβ), which deposits extracellularly to form amyloid plaques, and (2) tau, which accumulates intraneuronally to form neurofibrillary tangles (NFTs) made up of hyperphosphorylated-tau. Here, MAPT is linked to Alzheimer disease.