Polymorphisms of aquaporin5 gene in chronic obstructive pulmonary disease in a Chinese population

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.

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.

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).

The +2254A to G variant in intron 3 of AQP5 was associated with a decreased risk of COPD in a Chinese population.