APOE and Alzheimer disease: In the human genome, there are three alleles for this lipoprotein gene (i.e., ε2, ε3, ε4), with homozygous (i.e., ε3/ε4) and heterozygous (i.e., ε3/ε4, ε2/ε4) individuals having a 30–35% and 20–25% risk, respectively, of developing AD [98]; it has been described that ApoE4 (i) has a low affinity for HDL, resulting in neurotoxic ApoE4 aggregates.