TNFRSF11B and hyperthyroidism: Although we did not measure it in our study, 1,25-dihydroxyvitamin D (1,25-(OH)2D) inhibits T3-induced expression of OPG mRNA, but low levels of 1,25-(OH)2D in hyperthyroidism are likely to explain the high OPG levels in GD patients [27, 29].