BACE1 and Alzheimer disease: The recent PLB4 transgenic AD mouse model, based upon the targeted neuronal knock-in of human BACE1 (hBACE1) on an endogenous mouse BACE1 background, recapitulates an ‘AD-like’ phenotype with age-dependent Aβ accumulation, cognitive deficits and cerebral hypometabolism, as well as a diabetic phenotype [21].