APOE and Alzheimer disease: Interestingly the patterns of linkage between the ε4 allele of APOE and `523 poly-T alleles in the adjacent gene, TOMM40, differ between white and African Americans, both genotypic and allelic data support that among African Americans the ε4-`523-L haplotype had a stronger effect on the risk of AD than other ε4-`523 haplotypes (53).