APP and Alzheimer disease: APP encodes a type I integral membrane protein with three major isoforms, among which the 695‐residue isoform is the most common in neurons (Nhan, Chiang, Chiang, & Koo, 2015), and has been implicated in the pathogenesis of AD (Fernandez‐Funez, Mena, & Rincon‐Limas, 2015).