APOE and Alzheimer disease: Although cholesterol has been the most extensively studied, changes in other lipid classes are also observed in serum samples from AD patients, including sterols, sphingomyelin, phosphatidylcholine, glycerophosphoethanolamine, lysophosphatidylcholine, diacylglycerols, and triacylglycerols (Anand et al., 2017); therefore, APOE4 status could exacerbate other age-related changes in lipid homeostasis.