Aβ is formed by the sequential cleavage of the transmembrane amyloid precursor protein (APP) via β- and γ-secretase to generate monomeric Aβ, which then polymerizes to form soluble oligomers, protofibrils and insoluble amyloid fibrils, which are the main components of amyloid plaques in AD [153, 154]. This evidence concerns the gene APP and Alzheimer disease.