Refetoff syndrome

Refetoff Syndrome Refetoff Syndrome, also known as thyroid hormone resistance, is a rare genetic disorder characterized by reduced sensitivity of the body's tissues to thyroid hormones. This condition can lead to a variety of clinical manifestations, depending on the degree of resistance and the tissues affected.

Overview

Refetoff Syndrome is named after Dr. Samuel Refetoff, who first described the condition in 1967. It is a form of thyroid hormone resistance and is typically inherited in an autosomal dominant pattern. The syndrome is caused by mutations in the genes that encode the thyroid hormone receptors, most commonly the THRB gene.

Pathophysiology

The primary defect in Refetoff Syndrome is a mutation in the thyroid hormone receptor beta (THRB) gene. This mutation leads to impaired binding of thyroid hormones to their receptors, resulting in decreased hormone action despite normal or elevated levels of circulating thyroid hormones. The thyroid hormone receptors are crucial for mediating the effects of thyroid hormones on metabolism, growth, and development.

Clinical Features

Patients with Refetoff Syndrome may present with a wide range of symptoms, which can include:

• Goiter
• Elevated levels of thyroid hormones (T3 and T4) with normal or slightly elevated TSH levels
• Hyperactivity
• Learning disabilities
• Hearing loss
• Tachycardia

The clinical presentation can vary significantly among individuals, even within the same family.

Diagnosis

Diagnosis of Refetoff Syndrome involves a combination of clinical evaluation, laboratory tests, and genetic testing. Key diagnostic features include:

• Elevated serum levels of free T4 and T3
• Normal or slightly elevated TSH levels
• Genetic testing to identify mutations in the THRB gene

Treatment

There is no specific treatment for Refetoff Syndrome. Management focuses on alleviating symptoms and monitoring thyroid function. In some cases, beta-blockers may be used to manage symptoms such as tachycardia.

Prognosis

The prognosis for individuals with Refetoff Syndrome is generally good, with most patients leading normal lives. However, regular monitoring and management of symptoms are important to ensure optimal health outcomes.

See Also

• Thyroid hormone resistance
• Thyroid hormone
• Genetic disorders
• Refetoff, S., et al. (1967). "Syndrome of resistance to thyroid hormone: Clinical, biochemical, and genetic features." *Journal of Clinical Endocrinology & Metabolism*.
• Weiss, R. E., & Refetoff, S. (2000). "Resistance to thyroid hormone." *Reviews in Endocrine and Metabolic Disorders*.

NIH genetic and rare disease info

• NIH info on Refetoff syndrome

Refetoff syndrome is a rare disease.