BACKGROUND: Autoimmune thyroiditis, known also as chronic lymphocytic thyroiditis or Hashimoto's thyroiditis (HT), is the most common organ-specific autoimmune disorder affecting approximately 18% of overall population. The etiopathogenesis of HT has not been clearly elucidated, although the role of chronic inflammation, endothelial dysfunction and imbalance between pro-and anti-inflammatory cytokines has been established. Transforming growth factor β1 (TGFβ1) is required to maintain immune

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... ostasis, and is implicated in lymphocyte infiltration, production of autoantibody in the thyroid gland and thyrocyte destruction seen in patients with HT. The aim of the present study was to investigate the possible association of Leu10Pro (c.869T>C) and Arg25Pro (c.915G>C) single nucleotide polymorphisms (SNPs) of TGFβ1 gene with the occurence of HT. METHODS: We analyzed the genotype and allele frequencies of polymorphisms at codon 10 and 25 in 110 patients with established HT diagnosis and 197 healthy controls using PCR-restriction fragment length polymorphism (RFLP) technique. RESULTS: With regard to TGFβ1 Leu10Pro (c.869T>C) polymorphism, the frequency of C allele was increased in HT patients accoding to controls (p= 0.018, OR=1.5, 95% CI= 0.07-2.11), and combined CT+CC genotypes was associated with 2.9-fold increased disease risk (p= 0.00012, 95% CI= 1.67-5.04). Regarding Arg25Pro (c.915G>C) polymorphism, there was a significant increase of C allele frequency in patients with HT compared to healthy controls (p= 0.013, OR= 1.81, 95% CI= 1.13-2.89). In addition, C allele carying subjects (CG + CC) had 2.23-fold increased risk for developing HT according to GG homozygotes (p= 0.003, 95% CI= 1. 32-2.76). No association between polymorphisms and HT phenotypes were observed. CONCLUSIONS: We suggest that the Leu10Pro and Arg25Pro polymorphisms of TGFβ1 gene may be related to occurrence of HT. However, more studies with larger sample size including other loci of the TGFβ1 gene are necessary to support our findings before any statement can be made about the relationship between HT and TGFβ1 gene polymorphisms.