Studies in AD models have implicated ABCA1 mechanistically in the disease45 and ABCA1 is a major protein in the ApoE pathway, which contains the major genetic risk gene for AD, APOE4. ApoE lipidation is controlled by the activity of ABCA1, and the APOE4 genotype is thought to impair the recycling of ABCA1 and therefore its ability to lipidate ApoE46. The gene discussed is APOE; the disease is Alzheimer disease.