Endocrine Abstracts

Introduction: Graves’ disease (GD) is an autoimmune disorder of the thyroid gland, which is characterisied by a breakdown in immune tolerance. The lymphocytic infiltration of the thyroid leads to production of autioantibodies targeting thyroid stimulating hormone receptor (TSHR). The clinical course of GD varies among patients and it is difficult to predict the relapse risk after antithyroid therapy withdrawal. It is believed that GD occurs due to genetic suspectibility in combinaton with external factors. According to recent studies, microRNAs (miRNAs), which are small noncoding RNAs, also can play crucial role in the regulation of the immune system and development of autoimmunity. The aim of this study was to identify the association between single nucleotide polymorphism (SNP) rs12976445 in MIR125A gene and GD recurrence risk in Russian population.

Methods: We enrolled 270 patients with GD (210 women, 60 men) and 200 adults without autoimmune disorders. The mean age of GD onset was 41 ± 13.6 years. In our study we mesuared the levels of TSH, free T4, T3, TRAb before and after 12–18 months of antithyroid drug treatment. Also the ultrasound examination of the thyroid gland was performed. Genotypes of SNP rs12976445 MIR125A were identified using direct sequencing and polymerase chain reaction–restriction fragment length polymorphism method. Alleles and genotypes frequencies were compared between groups using the Chi-square or Fisher’ exact probability test.

Results: In our study the relapse rate estimated 33%. Only 13% of patients achieved remission of GD. The levels of TSH, freeT4, T3, TRAb did not differ significantly among patients. In this study significant differences in the distribution of alleles and genotypes between GD patients and control group were not revealed (P > 0.5). Among the patients with the reccurence of GD the CC genotype carriers were significantly more frequent (P = 0.001, OR = 5.5, 95% CI 1.8–13.8) than in patient with GD in remission.

Conclusion: Our results suggest that SNP rs12976445 MIR125A is associated with the risk of GD relapse but not with the severity of hyperthyroidism. At first time in Russian population with GD genotypes and allele frequencies of the rs12976445 MIR125A were identified.