Association between transforming growth factor-β1 gene C-509T and T869C polymorphisms and rheumatic heart disease

Background Scarring and collagen deposition in the valves and destruction of myocytes may result from the combined effects of a smoldering rheumatic process and a constant trauma to the mitral vlave or aortic valve by the turbulent flow in rheumatic heart disease (RHD). Transforming growth factor-β1 (TGF-β1) may be responsible for the increased valvular fibrosis and calcification in the pathogenesis of RHD. However, the role of TGF-β1 genetic variant in RHD has not been studied. This case-controlled study was carried out to investigate the possible relationship between the TGF-β1 gene C-509T and T869C polymorphisms and RHD among the Chinese population in Taiwan. Methods A group of 115 patients with RHD documented by using echocardiography and 100 age- and sex-matched healthy control patients were studied. TGF-β1 gene C-509T and T869C polymorphisms were identified with polymerase chain reaction-based restriction analysis. Results A significant difference was seen in the distribution of genotypes between patients with RHD and control patients for either TGF-β1 C-509T polymorphism (P <.0001) or T869C polymorphism (P <.0001). The frequency of TGF-β1 C-509T CC genotype was lower in the RHD group than in the control group (χ2 = 19.05, P <.0001), which suggests that this genotype may confer protective effects against RHD. A significant difference was seen in the distribution of allelic frequency between patients with RHD and control patients for TGF-β1 T869C polymorphism (P = .04). The odds ratio (OR) for risk of RHD associated with TGF-β1 T869C T allele was 1.49 (95% CI, 1.02–2.19). Further categorization of patients with RHD into mitral valve disease and combined valve disease subgroups revealed no statistical difference in these gene polymorphisms when compared with the 2 subgroups. Conclusions Patients with RHD have a lower frequency of TGF-β1 C-509T CC genotype and a higher frequency of T869C T allele, which supports a role for the TGF-β1 gene C-509T and T869C polymorphisms in determining the risk/protection of RHD in Taiwan Chinese patients.