Inherited thyroxine-binding globulin deficiency

Inherited thyroxine-binding globulin deficiency is a genetic condition that typically does not cause health problems.

Thyroxine-binding globulin is one of three major proteins in the bloodstream that carries hormones made by the thyroid gland, a butterfly-shaped tissue in the lower neck. Thyroid hormones play an important role in regulating growth, brain development, and the rate of chemical reactions in the body (metabolism). Thyroxine is the primary hormone produced by the thyroid gland. In the bloodstream, thyroxine and other thyroid hormones are typically attached (bound) to thyroxine-binding globulin and similar proteins. A shortage (deficiency) of thyroxine-binding globulin reduces the total amount of thyroxine in the blood.

Researchers have identified two forms of inherited thyroxine-binding globulin deficiency: the partial form and the complete form. The partial form reduces the amount of functioning thyroxine-binding globulin. The complete form causes a more significant loss of functioning thyroxine-binding globulin. These conditions typically do not cause problems with thyroid function and are usually identified when bloodwork is performed to rule out other conditions.

Although inherited thyroxine-binding globulin deficiency typically does not cause health problems, it can be mistaken for more serious thyroid disorders, such as hypothyroidism. Therefore, it is important to correctly diagnose the condition to avoid unnecessary treatments.