RESUMO
BACKGROUND: The CTLA4 gene is involved in the activity of T cells. AIM: To determine the association between Graves' disease (GD) susceptibility and CT60 polymorphism of the CTLA4 gene. PATIENTS: 189 children with GD and 620 healthy controls. METHODS: We determined the genotype with restriction fragment length polymorphism and compared results. RESULTS: Genotype G/G was significantly associated with GD (odds ratio [OR] = 1.71, 95% confidence interval [CI] 1.20-2.44, Pc = 0.006); however, allele A could reverse its effect. Allele G was significantly more frequent (OR = 1.61, 95% CI 1.18-2.19, Pc = 0.0049) but allele A (OR = 0.62, 95% CI 0.46-0.85, Pc = 0.0049) and phenotype A (OR = 0.58, 95% CI 0.41-0.83, Pc = 0.006) were less frequent in patients with GD than in controls. CONCLUSION: The CT60 SNP was associated with susceptibility to GD. The G allele increased the risk of GD.