Accumulation of Aβ peptides is considered a key event in the pathogenesis of AD; presenilin 1 (PS1) and presenilin 2 (PS2) play a critical role in the γ-secretase-mediated cleavage of amyloid precursor protein (APP) and consequently the generation of Aβ peptides [6–8]. This evidence concerns the gene APP and Alzheimer disease.