The whole blood DNA methylation of and in autoimmune thyroiditis: evidence and validation of iodine exposure in a population from different water iodine areas.

Our study aimed to identify and verify G protein-related methylated genes in AIT patients, while also investigate those genes in AIT patients exposed to iodine in different water iodine areas. Different areas were classified by median water iodine (MWI) concentrations: Iodine-Fortified Areas (IFA, MWI<10µg/L), Iodine-Adequate Areas (IAA, 40≤MWI≤100 µg/L), and Iodine-Excessive Areas (IEA, MWI>100 µg/L). We studied 176 AIT cases and 176 controls, with 89, 40, and 47 pairs in IFA, IAA, and IEA, respectively. Using the Illumina Human Methylation 850k BeadChip, we identified candidate methylated genes. MethylTarget and QRT-PCR validated DNA methylation and mRNA expression. Results showed hypomethylation and high expression of and in all 176 AIT cases. 's CpG sites were mainly hypomethylated in IFA and IEA, while 's sites were primarily hypomethylated in IEA. This study underscores how water iodine exposure may influence and methylation in AIT.