This insoluble material corresponds to the accumulation and aggregation of hyperphosphorylated microtubule–associated Tau proteins, which form neurofibrillary tangles (NFTs) [reviewed in Buee et al. (2010)], mainly in neuron soma but also in neuropile threads, similarly to that observed in an AD brain, whereas Tau proteins of a healthy neuron are mainly located in the axon. This evidence concerns the gene MAPT and Alzheimer disease.