Significant increases in expression of the cholesterol biosynthesis gene family, a proposed key process in AD etiology77, occur later in CPS (DHCR24, LBR, FDFT, HSD17B1, SC5D, CYP51A1, SQLE, and DHCR7) (Fig. 7e, middle, and Fig. 7g). This evidence concerns the gene SC5D and Alzheimer disease.