Pendred syndrome is a disorder typically associated with hearing loss and a thyroid condition called a goiter. A goiter is an enlargement of the thyroid gland, which is a butterfly-shaped organ at the base of the neck that produces hormones. If a goiter develops in a person with Pendred syndrome, it usually forms between late childhood and early adulthood. In most cases, this enlargement does not cause the thyroid to malfunction.

Mutations in the SLC26A4 gene cause about half of all cases of Pendred syndrome. The SLC26A4 gene provides instructions for making a protein called pendrin. This protein transports negatively charged particles (ions), including chloride, iodide, and bicarbonate, into and out of cells. Although the function of pendrin is not fully understood, this protein is important for maintaining the proper levels of ions in the thyroid and the inner ear. Mutations in the SLC26A4 gene alter the structure or function of pendrin, which disrupts ion transport. An imbalance of particular ions disrupts the development and function of the thyroid gland and structures in the inner ear, which leads to the characteristic features of Pendred syndrome.

The prevalence of Pendred syndrome is unknown. However, researchers estimate that it accounts for 7 to 8 percent of all hearing loss that is present from birth (congenital hearing loss).

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: March 01, 2016
Published By: National Institutes of Health