Abstract
BACKGROUND: Asthma and chronic obstructive pulmonary disease (COPD) are heterogenetic diseases and exhibit many similarities. Dutch hypothesis proposed that these two diseases may have common genetic origins. This study aims to investigate whether asthma and COPD share a common genetic background in Chinese patients. METHODS: In this case-control study, single nucleotide polymorphisms (SNPs) were genotyped using SNaPshot. Haplotype disease analysis and haplotype phenotype analysis were applied to assess the relationship between three polymorphisms of the FCER2 gene and the risk of COPD/asthma. Additionally, associations between polymorphisms of the FCER2 gene and phenotypes were analyzed. RESULTS: We detected ten SNPs of seven genes (FCER1A, FCGR2A, FCGR2B, CHI3L1, ADRB2, STAT6, and FCER2) expressed by airway epithelial cells. We detected genotypes and allele distributions in 251 COPD patients, 597 asthma patients, and 632 healthy controls. A significant difference was found in the FCER2 gene (rs28364072) between COPD patients and controls (P=0.009). Significant differences were observed in the genotype and allele distributions of rs1801274 (FCGR2A), rs12368672 (STAT6), and rs2228137 (FCER2) between asthma patients and controls (P=0.004, 0.007 and 0.010, respectively). Notably, polymorphisms of FCER2 gene were associated with the risk of both COPD (P=0.009 for rs28364072) and asthma (P=0.01 for rs2228137). Haplotype analysis revealed that haplotype T-G-T (alleles of rs28364072, rs2228137, and rs3760687, respectively) was significantly associated with a higher risk of asthma [odds ratios (OR) =2.25, 95% confidence interval (CI): 1.26-4.01, P=0.006]. Further analysis showed that the C-A-C haplotype and C-G-T haplotype were associated with increased blood eosinophils in either COPD or asthma patients (P=0.034, and P<0.001, respectively). Moreover, haplotypes C-A-C, C-G-C, and T-G-C showed significant associations with serum IgE levels in asthma patients (P=0.002, 0.041, and 0.004, respectively). CONCLUSIONS: Our data suggest that the FCER2 gene might associate with predisposition to asthma and COPD, while FCER2 haplotypes were associated with pulmonary function measurements and blood eosinophils counts in both diseases. Our findings support the common genetic basis for asthma and COPD, suggesting a potential therapeutic target for the two diseases.