APOE and Alzheimer disease: The goal of the present study was to identify genetic markers that are significantly associated with AD among APOE ε4 carriers in the Korean population by conducting the following analyses: (1) identifying possible candidate markers from a dataset of 500 whole-genome sequencing (WGS) comprised of 331 AD cases and 169 controls; (2) designing a customized genotyping AD chip (cAD chip) containing our WGS candidates and previously known genetic variants associated with AD; and (3) validating significant genetic markers in independent datasets from the Korean population by using the cAD chip.