Autoimmune thyroid disease and thyroid function test fluctuations in patients with resistance to thyroid hormone

Area of Science:

• Endocrinology
• Genetics
• Internal Medicine

Background:

• Resistance to thyroid hormone beta (RTHβ) is a genetic disorder caused by THRB gene mutations.
• Patients typically present with elevated thyroid hormones and non-suppressed TSH.
• Clinical, laboratory, and imaging findings require further elucidation in relation to genetic mutations.

Purpose of the Study:

• To investigate the clinical, laboratory, and imaging characteristics of RTHβ patients.
• To explore the association between RTHβ manifestations and THRB gene mutations.
• To assess the prevalence of autoimmune thyroid disease (AITD) in RTHβ patients.

Main Methods:

• Retrospective review of clinical charts of 68 RTHβ patients and 30 unaffected relatives.
• Genetic testing to identify THRB gene mutations.
• Comparison of clinical findings and laboratory results between patient groups and controls.

Main Results:

• Thirty-five heterozygous THRB gene mutations were identified.
• AITD prevalence was significantly higher in male RTHβ patients (42.1%) compared to controls (P=0.019).
• Over 20% of RTHβ patients showed temporary atypical thyroid function tests, particularly those with AITD and specific mutations.

Conclusions:

• Male RTHβ patients have a significantly higher frequency of AITD.
• Fluctuations in thyroid function tests are observed in RTHβ patients, influenced by AITD and specific mutations.
• Genetic testing is crucial for RTHβ patients with variable thyroid function test results to ensure accurate diagnosis and treatment.