As a result, the physiological hallmarks of AD have been widely considered to be the presence of amyloid plaques, extracellular deposits of insoluble beta-amyloid (Aβ) in the parenchyma of the brain as well as neurofibrillary tangles (NFT), intracellular deposits of hyper-phosphorylated tau protein which fill the neuron and take its shape, preventing it from functioning correctly (Fig. 2). This evidence concerns the gene MAPT and Alzheimer disease.