APOE and Alzheimer disease: It is likely that thousands of genes are involved in CHO metabolism, and probably not a single gene plays an absolute dominant role over the others; however, some genes exert a powerful effect on other congeners associated with a specific pathogenic cascade (e.g., APOE in AD) or a pharmacogenetic pathway (e.g., APOE vs. CYPs in AD treatment with donepezil) [3,10,25,36,37].