The predictive value of CTLA-4 and Tg polymorphisms in the recurrence of Graves' disease after antithyroid withdrawal

Abstract

Graves' disease (GD) is a multifactorial disease that develops as a result of complex interactions between genetic and environmental factors. The aim of our study is to determine the frequency of cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) A/G and TG C/T exon 33 SNPs (Tg E33SNP) in GD and to evaluate the relation between recurrence and these polymorphisms. A total of 187 subjects, including 97 previously treated GD patients and 90 age and gender matched control subjects were studied. We examined the relationship between the A/G and C/T polymorphism and various clinical and laboratory variables among patients with GD. TT genotype frequency in the GD patients was significantly higher than the controls. Number of recurrent patients was significantly higher in AG and GG carriers in comparison to AA carriers (57% and 45% vs 14%,p = 0.0001). CTLA-4 AG genotype had an eightfold (OR: 8.050; 95 % CI: 2.87-22.5; p = 0.0001) and GG genotype had a sevenfold (OR: 7.025; 95% CI: 1.67-29.4; p = 0.007) increase in the risk of recurrence in the patients with GD. In conclusion, early interpretation for definitive treatment procedures (i.e., radioactive iodine or surgery) may be considered in the patients with G allielle and E33SNP of Tg gene is conformed the susceptibility to GD in a Turkish population and having TT genotype increases the susceptibility to GD.