APOE and Alzheimer disease: Of the three alleles for the APOE gene (ε2, ε3, and ε4), inheritance of the epsilon 4 (ε4) variant is well-established as the most important genetic risk factor for the development of late-onset Alzheimer’s Disease (AD): presence of ε4 is associated with a higher risk for the development of AD, earlier age-of-onset, and interacts with gender, age, and race to accelerate progression [2].