Phosphoinositide-3-kinase regulatory subunit 1(PiK3r1) is the key subunit of phosphoinositide-3-kinase (PI3K) which is implicated in AD pathogenesis by affecting PI3K/AKT/glycogen synthase kinase 3β (GSK3β) signalling [37, 38]. This evidence concerns the gene PIK3R1 and Alzheimer disease.