The AD-related genes directly or indirectly interact with the function of APP and its cleaved constituents, amyloid beta 1–40 (Aβ1–40) and Aβ1–42, or with the tau protein, which in their aggregated forms, produce amyloid plaques [148] and neurofibrillary tangles [149], the characteristic hallmarks of AD. The gene discussed is MAPT; the disease is Alzheimer disease.