Apolipoprotein E (APOE) is a well‐studied gene that plays a central role in dementia and Alzheimer's Disease (AD) risk, cognition, and other aging‐related traits.[1] The gene encodes the APOE protein that is involved in lipid metabolism, aggregation and clearance of amyloid Aβ, and neuroinflammation.[2] The gene has three prevalent alleles –e2, e3, and e4—that are determined by genotype combinations of the single nucleotide polymorphisms (SNPs) rs7412 and rs429358. This evidence concerns the gene APOE and Alzheimer disease.