Abstract
BACKGROUND: Thyroid hormone resistance syndrome (RTH) is a rare hereditary endocrine disease that can manifest as hyperthyroidism, hypothyroidism, or remain asymptomatic. It can easily be confused with other types of thyroid diseases. The diagnosis of the disease depends on genetic testing. CASE REPORT: We report a 19-year-old male patient with elevation of thyroid hormones. Serological examination showed elevated thyroid hormone levels, and thyroid-stimulating hormone levels within the reference interval. The patient was finally diagnosed with RTH after genetic testing that identified a gene mutation inherited from his mother. Due to timely diagnosis, the patient's condition has been well controlled, and his prognosis is good. CONCLUSION: The clinical manifestations of RTH lack specificity, and serological examination typically shows elevated thyroid hormone levels and unsuppressed thyrotropin levels. Differential diagnosis requires a combination of serological examination, imaging studies, and functional tests to distinguish RTH from other conditions. The purpose of this treatment is to improve symptoms and should not involve the blind administration of antithyroid drugs, thyroid surgery, or radiotherapy.