APOE and Alzheimer disease: In AS, AD severity is also thought to increase with the severity of atherosclerotic plaques as they correlate with the density of cardinal neuropathological lesions seen in AD, such as phosphorylated tau spindles and amyloid-beta plaques, especially when the patient possesses the ε4 allele of the Apolipoprotein E gene (ApoE4) [41,42].