Not all elevated hormones are toxic: A case of thyroid hormone resistance.

Resistance to thyroid hormone syndrome (RTH) is a rare disorder and is usually inherited as dominantly negative autosomal trait. RTH is caused by mutations in the thyroid hormone receptor beta. Patients with RTH usually do not have signs and symptoms of thyrotoxicosis, but the thyroid function test shows an elevated T3 and T4, which get misinterpreted as hyperthyroidism, resulting in unnecessary treatment.