PDCD1LG2 and autoimmune thyroid disease: Different I content in water is also associated with different methylation patterns of major histocompatibility complex, class II, DP beta 1 (HLA-DPB1), and programmed cell death 1 ligand 2 (PDCD1LG2) genes related to the cell adhesion molecule pathway, which may play a role in the pathogenesis of autoimmune thyroiditis [177].