What are the genetic changes related to Pendred syndrome ?
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.  In people with Pendred syndrome who do not have mutations in the SLC26A4 gene, the cause of the condition is unknown. Researchers suspect that other genetic and environmental factors may influence the condition.