Chutintorn SriphrapradangPanudda SrichomkwunSamuel RefetoffSunee MamanasiriMahidol UniversityUniversity of ChicagoRatchaburi Regional Hospital2018-12-112019-03-142018-12-112019-03-142016-12-01Thyroid. Vol.26, No.12 (2016), 1804-180615579077105072562-s2.0-85006272176https://repository.li.mahidol.ac.th/handle/20.500.14594/42868© Copyright 2016, Mary Ann Liebert, Inc. 2016. A patient is reported with resistance to thyroid hormone beta caused by a novel THRB gene mutation and coexisting pituitary microadenoma. A 41-year-old Thai woman presented with elevated serum thyroid hormone levels and non-suppressed thyrotropin (TSH). Magnetic resonance imaging showed a 4 mm × 2 mm pituitary adenoma. Five of her relatives had similar thyroid tests abnormalities, but a sister had Graves' disease. Thyroperoxidase and thyroglobulin antibodies were positive in all affected family members, except for the proband's 4.5-year-old niece. Lack of thyrotoxic symptoms and TSH suppression by triiodothyronine indicated incidentaloma rather than a TSH-secreting pituitary adenoma. Genetic analysis revealed a THRB gene mutation (c.1037G>T), resulting in p.G251V.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicineArticleSCOPUS10.1089/thy.2016.0450