APOC1 and Alzheimer disease: We, therefore, limited our testing to SNPs within the interval between TOMM40 and APOC1 (which includes the APOE coding region, promoter, and 3’-UTR), whose allelic frequencies vary progressively by at least 5% across EastAs, EuroAs, and AAs and may modulate (and are most likely responsible for ethnic differences in) the effect of ε4 on AD risk.