Treatment of syndrome of resistance to thyroid hormone beta: 2023 consensus statements from the Japan Thyroid Association

Syndrome of resistance to thyroid hormone beta (RTHβ) is a familial syndrome of reduced responsiveness of target tissues to thyroid hormone, which is mainly induced by mutations in the THRB gene. The Japan Thyroid Association systematically reviewed literatures and published the consensus statements on the treatment of RTHβ in April 2023. RTHβ is sometimes inappropriately diagnosed with Graves’ disease because of high thyroid hormone levels, resulting in unnecessary treatment. In addition, there is a discrepancy between the estimated prevalence and the numbers of the reported cases, suggesting that many patients remain undiagnosed. Furthermore, it is not widely known how to treat this syndrome. Therefore, guidelines for the diagnosis and treatment of RTHβ are needed. We have established a diagnostic criteria and degree of severity for RTHβ in 2016. Here systematic review was done based on the GRADE approach. The statements include thirteen topics; four foreground clinical questions, five narrative background clinical questions, and four drugs that are not covered by health insurance in Japan. The recommendations and comments were prepared by the committee members, and the statements were further modified based on public comments. To our knowledge, this is the first consensus statements by a nation-wide academic society regarding the treatment of RTHβ based on a systematic review. This translated edition enables us to disclose Japanese consensus statements on the treatment of RTHβ to other countries and is expected to contribute to better treatment of RTHβ, but these statements should be referred in a realistic and flexible manner.