AD is the most common form of dementia, accounting for 60–70% of all cases, and the pathological features of AD include amyloid plaques constituted by amyloid beta as the main substance and neurofibrillary tangles aggregated of hyperphosphorylated tau protein, thus, it was proposed that amyloid plaques and neurofibrillary tangles cause AD4. The gene discussed is MAPT; the disease is Alzheimer disease.