Potential protective targets include variants in APP that lead to a reduction in pathologic Aβ [297, 298], APOE gene variants including APOE2 [251], APOE3-Christchurch [299], and APOE3-Jacksonville [300] with lower risk of developing AD [301], and variants in cholesterol efflux pathways such as ABCA1 [302], amongst others [293]. Here, APOE is linked to Alzheimer disease.