DNA methylation analysis within the IL2RA gene promoter in youth with autoimmune thyroid disease

BACKGROUND: Alpha-subunit of the interleukin-2 receptor (IL2RA) is involved in the regulation of T-cell function and has been related to autoimmune thyroid disease (AITD). Although the exact mechanisms are not fully understood, promoter methylation might account for differences in gene expression. The aim of this study was to investigate whether there are differences in the percentage of DNA methylation within the IL2RA gene promoter in young patients with AITD. MATERIALS AND METHODS: In a cross-sectional design, the presence of DNA methylation in the IL2RA gene promoter was quantified, by real-time PCR and melting curve analysis, in modified genomic DNA isolated from blood samples of a total of 149 children and adolescents with AITD, including patients with Hashimoto thyroiditis (EtaTau) (n = 60), Graves' disease (GD) (n = 9), concurrent diagnosis of HT and type 1 diabetes (T1DM + HT) (n = 25), and healthy controls (n = 55). RESULTS: The percentage of DNA methylation in the IL2RA gene promoter was significantly decreased in patients with GD (26.0 +/- 4.2%) but not in those with HT (36.3 +/- 1.4%) in comparison with controls (41.3 +/- 1.5%). CONCLUSIONS: The observed DNA hypomethylation in the IL2RA gene promoter in patients with GD might be related to its increased expression, thus contributing to the etiopathogenesis of GD in childhood and adolescence.