CHRNA5 and chronic obstructive pulmonary disease: Only SNP 1 (rs2568494) is in relatively high levels of linkage disequilibrium with SNPs identified by the genome-wide study of COPD (HapMap CEU data: r2 = 0.790 with rs8034191 and r2 = 0.692 with rs1051730), although the other IREB2 SNPs are also in LD with variants in other genes in the region, including CHRNA5. Identification of the genes and variants contributing to the association with COPD will require targeted resequencing of the region and further functional work.