We chose BACE1 for three reasons: 1) it has a clearly delineated research phase as a validated drug target for Alzheimer's disease [25], starting from 1999, 2) it has a paralogous gene family of only two members, BACE1 and BACE2, and 3) with over 5,000 compounds retrieved using the Entrez Gene ID 23621 for human BACE1, it was close to the median compound-to-human target numbers in the GVKBIO database that are distributed between 1 and over 50,000. Here, BACE2 is linked to early-onset autosomal dominant Alzheimer disease.