The amyloid precursor protein (APP) is pivotal in the pathophysiology of Alzheimer's disease (AD) since its abnormal cleavage by β-secretase and γ-secretase generates the hydrophobic amyloid-beta (Aβ) peptides including the two major Aβ peptides amyloid-beta 40 (Aβ40) and amyloid-beta 42 (Aβ42), which aggregate into neurotoxic amyloid plaques in the brain tissues, one of the key pathological hallmarks of AD [for a review, see (17)]. Here, APP is linked to early-onset autosomal dominant Alzheimer disease.