PSEN1 and Alzheimer disease: While mutations of Presenilin 1 (PSEN1), Presenilin 2 (PSEN2), and amyloid precursor protein (APP) account for most of the early-onset familial AD cases [6, 7], the etiology of the remaining 95% sporadic AD patients is complicated, which is due to various factors including aging, gender, education, and genotype of apolipoprotein E (ApoE) [8].