Background: Chronic obstructive pulmonary disease (COPD) is a major cause of chronic morbidity and mortality. It is influenced by both environmental and genetic factors. Aquaporin5 plays a critical role in the maintenance of normal lung water homeostasis. We investigated whether polymorphisms in the gene aquaporin5 had any bearing on individual susceptibility to the development of COPD.
Methods: 332 COPD patients and 373 unrelated, age-matched healthy people were recruited for the study. All participants were Chinese Han people. We designed denaturing high performance liquid chromatography (DHPLC) to detect SNP in exons1, 2, 3 of AQP5 and DNA sequencing to confirm it. The allele +2254A>G (rs3736309) in intron3 and +3088A>G (Thr-Thr, rs41308104) in exon4 from NCBI dbSNP were genotyped by PCR-based restriction fragment length polymorphism.
Results: We found no SNPs in exons1-4 of the AQP5 gene in our study population. However, the genotype frequency of +2254A>G SNP in intron3 was significantly different in cases and controls. The frequencies of AA AG GG in cases were 45.2%, 40.7%, and 14.1%, while in controls they were 34.5%, 51.6%, and 13.9% (chi2 = 9.899, P = 0.007), respectively. Higher OR for COPD was seen for persons with +2254AA genotype against +2254AG genotype (OR = 2.73; 95%CI = 1.88-3.97). Carriers of the variant allele +2254G had a lower risk of COPD than homozygous wild type carriers (OR = 0.44; 95%CI = 0.307-0.631).
Conclusion: The +2254A to G variant in intron 3 of AQP5 was associated with a decreased risk of COPD in a Chinese population.