Association between transforming growth factor beta1 gene polymorphisms and IgA nephropathy

BACKGROUND: Transforming growth factor beta1 (TGF-beta1) plays an important role in the modulation of cellular growth and differentiation in a wide variety of cell types and in the production/degradation of the extracellular matrix (ECM). We investigated whether G-800A, C-509T and Leu10-->Pro polymorphisms in the TGF-beta1 gene could be involved in the development and progression of immunoglobulin A nephropathy (IgAN). METHODS: DNA samples were obtained from 101 patients with biopsy proven IgA mesangial nephropathy and 118 healthy controls. The genotypes of G-800A, C-509T and Leu10-->Pro polymorphisms in the TGF-beta1 gene were determined by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) with MaeIII, Eco 81I and Pst I, respectively. RESULTS: No significant differences were observed in the genotype distribution of the three TGF-beta1 polymorphisms between patients and controls. The TAC haplotype (T=Leu10, A-800 and C-509 alleles, respectively) was significantly associated with IgAN (p=0.043; odds ratio (OR) =2.334, 95 % confidence interval (95%CI) 1.01-5.41). CONCLUSION: Our study suggests that the haplotype reconstruction of TGF-beta1 gene polymorphisms could be more informative than the investigation of single nucleotide polymorphisms for defining the associated risk of developing IgAN. Further research is needed on larger cohorts to confirm TGF-beta1 involvement and test other TGF-beta1 variants with possible additive or synergistic effects.