The β-secretase BACE1 (β-site amyloid precursor protein (APP) cleaving enzyme 1) plays a central role in Alzheimer’s disease (AD), as it initiates the amyloidogenic processing of APP to form pathogenic amyloid β peptides (Aβ) (Hussain et al, 1999; Lin et al, 2000; Sinha et al, 1999; Vassar et al, 1999; Yan et al, 1999). Here, BACE1 is linked to early-onset autosomal dominant Alzheimer disease.