Haplotype analysis was conducted in the family samples to help narrow the location of a CIP susceptibility locus and to determine whether a single functional variant could explain the pattern of association findings with individual SNPs in each population group. As a first step, we evaluated linkage distribution among the 11 SNPs to reduce the number of potentially informative markers for haplotype analysis. This analysis, shown in the Figure, revealed slightly more extensive linkage distribution in EAs than in AAs. These population-specific patterns are consistent with the linkage distribution structures reported in the HapMap database for this genetic region.34 Taking into account the linkage distribution block structure and the association findings with individual SNPs, we selected 3 SNPs (rs9400554, rs6937479, and rs9387522) for haplotype analysis. These markers include the 2 most significant results in the combined sample and account for the potentially uniquely important information from each linkage distribution block spanning the entire region, showing significance with any marker in either population sample. The haplotype that included this SNP combination was significantly associated in AAs (global, P=.003), EAs (global, P=.02),
