PSEN1 and Alzheimer disease: There are 13 genes directly associated with AD (NDUFS2,APAF1,BACE1,CACNA1F,COX5B,COX6A2,GRIN1,GRIN2A,LPL,PLD3,PSEN1,RYR3,UQCRC1) and one gene associated with DS (DSCR9).