Association of HHIP polymorphisms with COPD and COPD-related phenotypes in a Chinese Han population.

The hedgehog signaling pathway plays an important role in lung morphogenesis and cellular responses to lung injury. Genome-wide association studies (GWAS) and integrative genomics approaches have demonstrated the associations between HHIP polymorphisms and chronic obstructive pulmonary disease (COPD) and in non-Asian populations. Here we investigated whether HHIP polymorphisms would also be associated with COPD susceptibility and COPD-related phenotypes in a Chinese Han population. In the present case-control study a total of 680 COPD patients and 687 healthy control subjects were recruited. Six single nucleotide polymorphisms (SNPs) (rs1828591, rs13118928, rs6817273, rs10519717, rs12504628, rs13147758) were selected for genotyping. Allele frequencies and genotype distributions were compared between patients and controls. To estimate the strength of association, odds ratios (OR) (with 95% CI) were calculated and potential confounding variables were tested by using logistic regression analysis. Association between haplotypes and COPD outcome was also assessed. We identified that SNP rs12504628 was associated with FEV1/FVC ratio among cases (P=0.0460). Moreover, the HHIP SNP rs10519717 was associated with the severity of disease (adjusted P-value=0.0300). The six SNPs showed strong linkage disequilibrium (r(2)≥ 0.9). Three major haplotypes were observed but showed no significant difference between case and control groups (P=0.4532, 0.0875, and 0.3484, respectively). In conclusion, our study suggests that the HHIP gene may be involved in COPD susceptibility in Chinese Han population.