Polymorphisms of endothelin 1 (G5665T and T-1370G) and endothelin receptor type A (C+70G and G-231A) in Graves' disease

•This study examined the possible association of EDN1 family genes and GD.•EDN1 (G5665T and T-1370G) and EDNRA (C+70G and G-231A) polymorphisms were assayed by real-time PCR.•No significant associations between GD and variant alleles of studied polymorphisms were observed.•EDN1 G5665T and T-1370G polymorphisms are related with alterations of autoantibody production.•EDNRA C+70G polymorphism is related with increased risk for GD ophtalmopathy.

PurposeEndothelin 1 (EDN1) is a strong angiogenic and mitogenic factor, playing a key role in hypervascularization, thyroid follicle cell hyperplasia, and lymphocyte infiltration in the thyroid gland of patients with Graves' disease (GD). EDN1 induces angiogenesis and mitogenesis via endothelin receptor type A (EDNRA). This study examined the possible association of EDN1 (G5665T and T-1370G) and EDNRA (C + 70G and G-231A) single nucleotide polymorphisms (SNPs) with the occurrence of GD, and evaluates the relationship between genotypes and clinical/laboratory manifestations of GD.Materials and methodsWe analyzed genotype and allele distributions of EDN1 and EDNRA polymorphisms in 165 patients with GD and 181 healthy controls by real-time PCR combined with melting curve analysis.ResultsNo significant associations between GD and variant alleles of the studied polymorphisms were observed. However, the anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-TG) levels in EDN1 G5665T GG genotype were higher than those in T allele carriers (GT + TT) (p = 0.001 and p = 0.026, respectively). In addition, anti-TPO levels in EDN1 T-1370G wild-type homozygous patients were found to be higher than in mutant gene carrying patients (GT + GG) (p = 0.006). The presence of EDNRA + 70G allele was associated with 3.37-fold increased risk for development of ophthalmopathy in GD patients (p = 0.009).ConclusionAlthough there were no associations between EDN1 (G5665T and T-1370G) and EDNRA (C + 70G and G-231A) SNPs and susceptibility to GD, EDN1 G5665T and T-1370G polymorphisms were related to alterations of autoantibody production and EDNRA C + 70G polymorphism is related with increased risk for ophthalmopathy in GD patients.