Endocrine Abstracts

Autoimmune thyroid diseases (AITD), such as Hashimoto’s thyroiditis (HT) and Grave’s disease (GD) frequently form overlap syndromes with rheumatoid arthritis (RA). Among genetic factors, the role of the HLA antigens and CTLA4 gene polymorphisms in the formation of such overlap syndromes has been suggested.

Objective: Aim of this study was to investigate the alleli and genotypes frequency of the CTLA4 exon1 A49G polymorphism in Slovak patients with RA, HT and both (RA+HT) and to compare it with healthy controls.

Subjects and methods: Homogeneous groups of 57 unrelated adults with RA, 57 patients with HT, 34 patients with both RA and HT, and 51 randomly selected normal adults without any history of autoimmune disease were studied. All of them were ethnic Slovak living in the same geographical area. The CTLA4 exon1 A49G polymorphism was genotyped by using small amplicon melting analysis after real-time PCR.

Results: The CTLA4 49 GG genotype and G allele frequency in the group with RA was not significantly higher in comparison with controls (10.53 vs 9.8%, OR 1.39, P=0.62 for GG genotype, 39.47 vs 34.31% OR 1.25 for G allele). The frequency of GG genotype was slighlty but not significantly higher in patients with HT as compared with control group (19.3 vs 9.8%, OR 2.27, P=0.17). However the frequency of GG genotype and G allele in patients with the coexistence of RA and HT was significantly higher than that in control group (29.41 vs 9.8%, OR 4.49, P=0.02 for GG genotype, 51.47 vs 34.31%, OR 2.02 for G allele, P=0.03).

Conclusion: Our results swow that patients with RA who are carriers of GG genotype of CTLA-4 A49G gene polymorphism may be susceptible to develop HT.