BACE1 and Alzheimer disease: A substantial body of evidence has indicated the deposition of Aβ as a principal etiological factor in the development of AD (Hardy and Allsop, 1991; Hardy and Higgins, 1992; Selkoe and Hardy, 2016), and BACE1 serves as a critical rate-limiting enzyme in the biosynthetic pathway that culminates in the formation of Aβ peptides.