PSEN2 and Alzheimer disease: The five companion genes with AD-targeted therapeutics are NCSTN (MIM: 605254), MAPK14 (MIM: 600289), PSEN1 (MIM: 104311), PSEN2 (MIM: 600759), and PSENEN (MIM: 607632), which are all targeted by tarenflurbil, semagacestat, and avagacestat.