APOE and Alzheimer disease: A number of genes involved in cholesterol metabolism or transport are AD susceptibility genes, including apolipoprotein E (APOE), apolipoprotein J (APOJ, CLU), ATP-binding cassette subfamily A member 7(ABCA7), and sortilin-related receptor (SORL1) has been identified as a pivotal components of cholesterol metabolism in the brain (78).