Coclia Pediatric Neck Masses

The most common syndromic form of hereditary SNHL, Pendred syndrome (PS) was described by Pendred in 1896. The condition is autosomal recessive, and affected individuals also have goiter. The prevalence of PS is estimated at 7.5 to 10 per 100,000 individuals, suggesting that the syndrome may account for 10% of hereditary deafness. The hearing loss is usually congenital and severe to profound, although progressive mild to moderate SNHL is sometimes seen. Bilateral dilation of the vestibular aqueduct is common, and may be accompanied by cochlear hypoplasia. Most cases of PS result from mutations in the SLC26A4 gene that encodes an anion transporter known as pendrin that is expressed in the inner ear, thyroid, and kidney. Expression of SLC26A4 has been shown throughout the endolymphatic duct and sac, in distinct areas of the utricle and saccule, and in the external sulcus region within the developing cochlea. Pendrin is thought to be involved in chloride and iodide transport and not sulfate transport.