MAPT and Alzheimer disease: The neuropathological hallmarks of the AD brain consist of diffuse neuritic extracellular β‐amyloid (Aβ) plaques, frequently surrounded by dystrophic neuritis, and hyper‐phosphorylated tau protein accumulation in intracellular neurofibrillary tangles (NFTs) at cerebral level 3; these key features are often accompanied by the presence of reactive microgliosis and the loss of neurons, grey matter and synapses.