APOE and Alzheimer disease: Although the overall effect of APOE ε4 on AD outcomes in African Americans remains unclear (Farrer et al., 1997; Tang et al., 2001; Hendrie et al., 2014; Rajabli et al., 2018), this result may suggest that APOE ε4-related hippocampal dysfunction can manifest in healthy older African Americans and may be an indicator of future disease status.