There is evidence that the amount of histologically identified Aβ in vessels and plaques in the cerebral cortex of patients with Alzheimer’s disease is a direct function of their APOE genotype, and subjects with ε4ε4 genotype have an increased amyloid deposits in vessels and density of strongly Aβ-immunoreactive plaques than those with ε3ε3 genotype [47]. Here, APOE is linked to Alzheimer disease.