The pathology of AD is typically characterized by: (1) the presence of neurofibrillary tangles (NFTs) formed by aggregates of hyperphosphorylated tau, a microtubule-associated protein in neurons,5 and (2) accumulation of abnormal peptides (Aβ1–42) proteolytically cleaved from β-amyloid precursor protein (APP), which form extracellular senile plaques.6 These NFTs and plaques, found primarily in the hippocampus and frontal cortex of the AD brain, trigger neurodegeneration in these areas. Here, APP is linked to Alzheimer disease.