Objective: Graves' disease is associated with a polymorphism at position 49 in exon 1 of the cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) gene in Caucasians and Japanese. A high incidence of childhood Graves' disease has been documented in Hong Kong Chinese. The aims of this study were to investigate the CTLA-4 gene A-G polymorphism association in Chinese children with Graves' disease.
Patients and design: One hundred and twenty-three Chinese children with Graves' disease (104 girls and 19 boys) and 158 racially matched healthy controls were recruited for the study. Genomic DNA was extracted from venous blood samples. The dimorphism at position 49 A-G was analysed by polymerase chain reaction, single-strand conformation polymorphism and restriction fragment-length polymorphism analysis.
Results: The genotype distribution and allele frequencies of children with Graves' disease differed significantly from those of the controls (P = 0.0023 and P = 0.022, respectively). The presence of at least one G allele (GG or AG) was associated with an increased risk of Graves' disease (OR = 6.8, 95% CI = 2.0-36.1; P = 0.001).
Conclusions: This study confirms that CTLA-4 49 A-G polymorphism is associated with Graves' disease in Chinese children. The CTLA-4 49 G allele confers an increased risk of childhood Graves' disease.