Transforming growth factor-beta1 gene polymorphisms associated with chronic obstructive pulmonary disease in Chinese population.
OBJECTIVE
To determine the frequencies of polymorphism and haplotype in the transforming growth factor-beta 1 (TGF-beta1) gene promoter in the Chinese population and to investigate the susceptibility of this population to chronic obstructive pulmonary disease (COPD).


METHODS
The target fragments of the TGF-beta1 gene promoter were amplified and analyzed by polymerase chain reaction-restriction fragment length polymorphism technique in 84 COPD patients and 97 age- and sex-matched healthy controls. The test for Hardy-Weinberg equilibrium was performed using HWE program of the LINKUTIL package and statistical analysis was carried out with the SPSS statistical package. An expectation maximization algorithm was used for the pairwise linkage disequilibrium test and haplotype analysis.


RESULTS
More carriers of the -800A allele, or fewer carriers of the -509T allele, were detected in the COPD patients compared with the non-symptomatic control subjects [for the -800A allele, 29.8% vs 14.4%, respectively, Chi2=6.257, degrees of freedom (df)=1, P=0.012; for the -509T allele, 27.3% vs 44.3%, respectively, Chi2=5.582, df=1, P=0.018]. The prevalence of the -800A allele was significantly higher in the COPD patients than in control subjects (P=0.009), whereas the frequency of the -509T allele was significantly higher in control subjects than in the COPD patients (P=0.008). In addition, this distribution tendency for the -800A or -509T allele was similar in heavy smokers (smoking history >20 pack years); (number of packs of cigarettes per day multiplied by the number of years of smoking) Chi2=7.235, P=0.007, and Chi2=5.636, P=0.018, respectively). The linkage disequilibrium was found between -800 G-A and -509 C-T (D>0.60, P<0.0001), and the frequency of the AC haplotype, consisting of the least common base at -800 and the most common base at -509, was significantly higher in patients with COPD than in controls (0.056 vs 0.021, P<0.05).


CONCLUSIONS
The single nucleotide polymorphism (SNP) in the TGF-beta1 gene promoter might be associated with COPD, and the -800A/-509C haplotype is possibly one of the susceptibility factors for COPD.
Su
Zhi-guang
ZG
Laboratory of Pulmonary Medicine, West China Hospital, Sichuan University, Chengdu 610041, China. zhiguang_su@hotmail.com
Wen
Fu-qiang
FQ
Feng
Yu-lin
YL
Xiao
Min
M
Wu
Xiao-ling
XL
D000368:Aged; D000483:Alleles; D044466:Asian People; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D029424:Pulmonary Disease, Chronic Obstructive / Q000235:genetics*; D012907:Smoking; D016212:Transforming Growth Factor beta / Q000235:genetics*; D053773:Transforming Growth Factor beta1
C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1