Association of transforming growth factor beta1 gene polymorphism with rheumatoid arthritis in a Turkish population.

Objective: Cytokine genes play important roles in the pathogenesis of rheumatoid arthritis (RA). In RA, the plasma and synovial fluid levels of transforming growth factor beta1 (TGFbeta1) have been shown to be raised. The aim of this study was to investigate the relationship between the TGFbeta1 T869C polymorphism and RA in a Turkish population.

Methods: One hundred and thirty-one patients with a clinical diagnosis of RA and 133 healthy controls were enrolled in this study. Analyses of TGFbeta1 T869C gene were made by the polymerase chain reaction-restriction fragment length polymorphism technique.

Results: There was no significant difference in genotypic frequency of TGFbeta1 T869C polymorphism between the patients with RA (TT:TC:CC=42.7%:41.2%:16%) and controls (TT:TC:CC=36.1%:48.1%:15.8%) (p=0.48). The age at first occurrence of clinical symptoms of RA did not differ significantly in relation to TGFbeta1 T869C genotypes (p=0.07). Furthermore, there was no significant association between TGFbeta1 T869C genotypes and the presence or absence of radiographic erosions in the patient group (p=0.67). But presence of T allele was associated with 1.92-fold increased risk for RF positivity (p=0.02, OR=1.92, 95% CI=1.08-3.40).

Conclusion: The allele frequencies for TGFbeta1 T869C polymorphism in RA patients were similar to those in the control group. However, the T allele carriers had 1.92-fold increased risk for RF positivity. Further studies on larger numbers of cases and on the other polymorphic regions of this gene are needed before definite conclusions can be drawn about the role of TGFbeta1 in the etiology of RA.