Association of single nucleotide polymorphisms in PDE4D gene with COPD in Chinese population

Objective To investigate the association of single nucleotide polymorphisms (SNP) in PDE4D gene with COPD. Methods Seventy-one COPD patients and 65 control patients of a community in Beijing, aged 40-80 years, were enrolled in the study.Eight SNPs in PDE4D gene were selected SNP1=rs11740402, SNP2=rs17528473, SNP3=rs17780213, SNP4=rs1529843, SNP5=rs11743928, SNP6=rs26956, SNP7=rs35387, SNP8=rs35386.DNA specimens were all extracted from frozen blood and primers of two ends were designed to amplify their unique targets under a defined set of reaction conditions.Genotyping was done by Sanger sequencing.The difference of genotype and the variation of allele frequencies were analyzed by Chi-square test.Association between SNPs and COPD was examined by unconditioned logistic regression analysis. Results The polymorphisms of the 8 SNPs in COPD and control patients were all on Hardy-Weinberg balance.The Linkage Disequilibrium analysis revealed a genetic disequilibrium at SNP1 and SNP2, which made LD block 1, and the other genetic disequilibrium at SNP6, SNP7 and SNP8, which made LD block 2.The genotype of SNP5 was A/A in all the patients of the two groups.There was no difference in haplotypes and the frequencies of alleles in the 8 SNPs between the two groups.However, significant difference between the two groups was found at SNP8 (P<0.05) in the analysis of genotype frequencies.In further unconditional logistic regression analysis, SNP8 showed significant difference in Ressessive model (P<0.05, OR=4.07, 95%CI=1.26-13.18) and the frequency of genotype G/G was 20.3% and 6.3% in COPD and control group respectively. Conclusions It was suggested that genetic variants of PDE4D gene might be associated with COPD in the Chinese population. Key words: Chronic obstructive pulmonary disease; Gene; Single nucleotide polymorphisms; Phosphodiesterase