The main pathological features of AD in the brain are intracellular fibrillary tangles (NFTs) formed by hyperphosphorylated tau which lead to hippocampal and cortical neurons’ death and the extracellular accumulation of senile plaques derived from the aggregation of amyloid beta peptide (Aβ), the proteolytic product of APP [113]. The gene discussed is MAPT; the disease is Alzheimer disease.