We did not find differences in expression between COPD and non-COPD for DDTL, but our eQTL results suggest that the regulation of DDTL expression resembled that of MIF. Considering that MIF and DDTL are located in close proximity (less than 0.1 Mb between the two genes), it is not surprising that our cis-eQTL analysis, which identifies SNPs within 1 Mb from the binding site of the probe, found SNPs regulating the expression of both genes, indicating possible dual regulation. Here, MIF is linked to chronic obstructive pulmonary disease.