Analysis of TGF-β₁ gene polymorphisms in Hong Kong Chinese patients with asthma

Background

The C-509T polymorphism of TGF-β₁ gene has been associated with asthma and atopy in white populations.

Objective

We investigated the association between asthma and previously identified polymorphisms at C-509T and T869C of the TGF-β₁ gene among 250 Chinese patients with asthma and 308 healthy controls in Hong Kong.

Methods

Genotyping was performed on peripheral blood genomic DNA by using PCR-RFLP.

Results

There were no differences in the frequencies of genotypes and alleles between patients and controls. The C-509T and T869C polymorphisms were in tight linkage disequilibrium (P < .01). Among atopic subjects, significant differences were found in genotype and allele frequencies for T869C polymorphism between patients and controls (P = .014 and P = .019, respectively), and individuals bearing the CC genotype were associated with increased risk for the development of asthma (odds ratio, 2.58; 95% CI, 1.17-5.66; P = .018) after adjusting for age, sex, and smoking status. Individuals with asthma bearing the CT genotype of the C-509T polymorphism had significantly increased risk for severe airflow obstruction compared with individuals who had mild obstruction (odds ratio, 4.00; 95% CI, 1.06-15.08; P = .035).

Conclusion

Our results indicate that the polymorphisms at C-509T and T869C of the TGF-β₁ gene are associated with asthma susceptibility in atopic subjects of the Hong Kong Chinese population, and the C-509T polymorphism may play a role in the pathogenesis of airflow obstruction.

Key words: Transforming growth factor-β₁, polymorphism, asthma, disease severity, Hong Kong Chinese population

Abbreviation used: OR, Odds ratio