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Resistance to Thyroid Hormone Syndrome

Resistance to Thyroid Hormone (RTH) syndrome is a rare, inherited disorder where the body's tissues are less sensitive to thyroid hormones, resulting in elevated levels of thyroid hormone in the blood but normal or high Thyroid Stimulating Hormone (TSH) levels

Prevalence

<1 / 40 000

1,000–2,000

US Estimated

1,500–3,000

Europe Estimated

Age of Onset

Childhood

ICD-10

E07.9

Inheritance Pattern

Autosomal dominant

Autosomal recessive

Mitochondrial/Multigenic

X-linked dominant

X-linked recessive

5 Facts you should know

FACT

Resistance to thyroid hormone (RTH) is a rare inherited endocrine disorder, most often caused by dominant mutations in the thyroid hormone receptor beta (THRB) gene, impairing tissue responsiveness to circulating thyroid hormones

FACT

Biochemically, RTH is characterized by elevated serum free T4 and T3 with inappropriately normal or elevated TSH, distinguishing it from primary hyperthyroidism

FACT

Clinical presentation is highly variable — some patients are asymptomatic, while others show goiter, tachycardia, hyperactivity, learning difficulties, or features of hypothyroidism, reflecting tissue-specific resistance

FACT

Differential diagnosis includes TSH-secreting pituitary adenoma, making genetic testing critical for confirmation

FACT

Management is individualized and may involve beta-blockers for tachycardia, thyroid ablation in select cases, or watchful monitoring, depending on symptom severity and target organ involvement

Interest over time

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