APOE and Alzheimer disease: The mechanisms by which APOE4 impacts AD risk are thought to be numerous and include regulation of β-amyloid clearance, metabolism, inflammation, glial dynamics, and vascular function (Serrano-Pozo et al., 2021; Parhizkar and Holtzman, 2022; Tzioras et al., 2019; Norwitz et al., 2021).