For sickle cell anemia, a total of 179 SNPs reached genome-wide significance (p<5×10−8), encompassing an ∼2.5-Mb region on chromosome 11p15.4 (from 3.59 Mb for rs12422109 to 5.98 Mb for rs997433). The region contains dozens of genes and dozens of visually discernable LD blocks in HapMap YRI population. The top association signal (rs7120391, p = 1.1×10−136) is 9 kb from OR51V1, which is very near the causal gene, HBB (Figure 7). Clearly, highly significant association signals can travel across multiple LD blocks to distant genomic regions.
