CD40 C/T_-1 and CTLA-4 A/G₄₉ SNPs are associated with autoimmune thyroid diseases in the Chinese population

This study was to investigate whether the common polymorphisms of CD40 and CTLA4 genes confer susceptibility to AITD in the Chinese population. A set of unrelated subjects including 303 GD patients, 208 HT patients, and 215 matched healthy controls were recruited. SNPs were genotyped by the method of PCRRFLP. (1) As for CD40 C/T-1 SNP, only a significant difference was found in allele frequencies between GD and control groups (P = 0.033). (2) On the part of CTLA-4 A/G₄₉ SNP, significant differences were found in genotype and allele frequencies between GD and control groups (P = 7.0 × 10^-5 and P = 0.002, respectively), and similar results were found between HT and control groups (P = 0.015 and P = 0.003, respectively). (3) The logistic regression analysis showed there was no interaction between CD40 and CTLA4 genotypes (P = 0.262). These results indicate that both CTLA-4 A/G49 and CD40 C/T_-1 SNPs are associated with genetic susceptibility of GD, and CTLA-4 A/G ₄₉ is also associated with HT.