The association between rs4684677 T/A polymorphism in preproghrelin gene and predisposition to autoimmune thyroid diseases in children

Background: A potential role of preproghrelin polymorphisms on autoimmune thyroid diseases (AITDs) has not been established equivocally yet. Aim: To estimate the association of two polymorphisms of preproghrelin gene with the predisposition to Graves' disease (GD) and Hashimoto's thyroiditis (HT) in children. Methods: The study was performed in 145 patients with GD, 87 with HT and 161 healthy volunteers. The two single nucleotide polymorphisms (SNPs) rs696217 (C_3151003_20) and rs4684677 (C_25607748_10) in the preproghrelin gene were genotyped by TaqMan SNP genotyping assay using the real-time PCR. Results: Rs4684677 T alleles were more frequent in HT patients (99% in women and 100% in men) in comparison to healthy subjects (p = 0.002) with OR = 8.0 and 95% confidence interval for OR: 1.8-206.7. In women group, rs4684677 T alleles were more frequent compared to healthy controls (99%) in HT (p = 0.02) with OR = 6.7 and 95% confidence interval for OR: 1.2-168.37. Frequency of the SNP rs696217 did not differ between the groups. There was a significant relationship between rs696217 polymorphisms and anti-TSHR antibodies level (p = 0.036) in women from GD/HT groups. A significant relationship between rs696217 polymorphisms and anti-TG antibodies level in GD women group (p = 0.038) and between rs696217 polymorphisms and fT4 concentration (p = 0.03) were found. Conclusions: Rs4684677 T/A polymorphisms in preproghrelin gene could contribute to development of AITDs in children and T allele is the main risk factor.