We also tested for eQTL SNPs influencing the expression of genes in previously identified COPD loci. On chromosome 15q25, we defined a region starting 50 kb centromeric from IREB2 extending 50 kb telomeric from CHRNB4 (approx. 300 kb total) and tested all genotyped SNPs within this region for association with expression levels of probe sets for six genes: IREB2, AGPHD1, PSMA4, CHRNA5, CHRNA3, and CHRNB4. For the other two COPD loci, we expanded the cis-eQTL analysis to all SNPs with 200 kb of the TSS of the genes HHIP and FAM13A.
