Two major enzymes within the “amyloidogenic” pathway, the β-site amyloid precursor protein cleaving enzyme-1 (termed β-secretase or BACE1) and the γ-secretase complex, drive the conversion of the amyloid precursor protein (APP) to the clinically relevant Aβ40 and Aβ42 species in AD (2). The gene discussed is APP; the disease is Alzheimer disease.