The hallmarks of AD are (a) the increased brain expressions of per se normal Aβ and tau, peptides with known physiological brain functions [27,28], and (b) formation of early-stage toxic monomers, oligomers, late-stage fibrils and β-amyloid from Aβ peptides, and NFT from phosphorylated tau. This evidence concerns the gene MAPT and Alzheimer disease.