RESUMO
Hashimoto's thyroiditis (HT) and Graves' disease (GD) susceptibility depends on a complex interaction between environmental and genetic factors. Genes for tumor necrosis factor alpha (TNF-α) and toll-like receptors (TLRs) have been incorporated into the pathophysiology of autoimmune disorders. Our aim is to assess the association between TLR7 (rs179009) and TNF-α (rs1800629) polymorphisms and susceptibility to autoimmune thyroid disorders. One-hundred ninety-nine individuals, divided into 68 HT patients in group I, 57 GD patients in group II, and 74 age- and gender-matched healthy subjects in group III, underwent laboratory investigations, including the detection of TLR7 and TNF-α polymorphisms using real-time PCR technique. TLR7 (rs179009) genotypes, A/G and G/G, were significantly more prevalent in HT patients (group I) compared to normal controls. Meanwhile, TNF-α (rs1800629) genotypes in GD patients (group II) showed a six fold increase in the risk of the disease in the G/A and A/A genotypes. Our findings propose the fact that the polymorphisms of TLR7 (rs179009) play a role in the susceptibility and the development of Hashimoto's thyroiditis, whereas TNF-α (rs1800629) polymorphisms play a role in the susceptibility and development of Graves' disease.