Association between the polymorphism A/G at position 49 of exon 1 of the CTLA-4 gene and antithyroid antibody production in children with Hashimoto's thyroiditis.

UNLABELLED

CTLA-4 gene is considered to be one of the strongest factors determining the predisposition to antithyroid antibody (Ab) production. The aim of the study was to evaluate the association of the polymorphism A/G of exon 1 of CTLA-4 gene and antithyroid Ab level in children with Hashimoto's thyroiditis (HT).

MATERIAL AND METHODS

45 children with HT (aged 14.9 ± 2, range 8.1-7.9) and 55 healthy controls (aged 14.8 ± 2.34, range 8.0-17.4) were enrolled. Controls were euthyroid and free from any autoimmune disease. CTLA-4 gene (+49)A/G polymorphism was evaluated by a single-strand conformation polymorphism method and restriction fragment-length polymorphism.

RESULTS

The frequency of GG genotype in HT children was significantly higher than in controls: 31 vs. 14.5% respectively (p < 0.04, OR = 2.65, CI = 0.99-7.06). Anti-Tg Ab titers were higher in patients homozygous for G allele than with AA genotype. The GG genotype seemed to be protective from hypothyroidism at the moment of HT diagnosis, but this observation was not statistically confirmed.

CONCLUSIONS

Our study provides the evidence supporting the association between CTLA-4 gene (+49)A/G polymorphism and the susceptibility to HT in Polish children and confirms the existence of a link between (+49)A/G polymorphism and anti-Tg Ab level.