Aβ derived from amyloid precursor protein (APP) is involved in up-regulation of protein aggregates and related dysfunction in APP processing resulting from mutations in APP, presenillin1 (PSEN1) or presenillin2 (PSEN2) for early-onset AD and apolipoprotein E (APOE) for late-onset AD [4]. The gene discussed is APOE; the disease is Alzheimer disease.