However, we did not finding significant cis-eQTL SNPs for two other known COPD loci, HHIP and FAM13A. The associated SNPs found through GWAS may exert their effects on phenotype via other mechanisms besides influencing gene expression. Alternatively, the GWAS SNPs may actually be eQTLs acting in other tissues besides sputum, such as alveolar or bronchial epithelial cells, which were not assessed in our study.
