While much research has focused on the ability of apoE4 to increase the aggregation and decrease the clearance of Aβ5–11, possession of an APOE4 allele also affects a wide array of additional processes in the brain (see reviews by Huang12 and Wolf et al.13), and it is unclear if these other functions may play a role in the pathogenesis of AD among APOE4 carriers. Here, APOE is linked to Alzheimer disease.