APOE and Alzheimer disease: For example, the APOE ε4 allele confers lower AD risks for African Americans than Caucasians [6, 7], the ABCA7 risk allele confers greater AD risks for African Americans than Caucasians [8], and AD is associated with less amnestic baseline performance and slower longitudinal decline in African Americans than Caucasians on neuropsychological analysis [9].