Pendred syndrome

Abstract

Pendred syndrome (PDS) is an autosomal recessive disorder clinically characterized by sensorineural hearing loss and goiter. PDS is mainly caused by mutations in the SLC26A4 gene, although a few cases are due to mutations in the FOXI1 gene. SLC26A4 encodes pendrin, a sodium-independent transporter of iodide/chloride, chloride/formate and bicarbonate, that is expressed in the inner ear, thyroid gland, syncytiotrophoblast cells, endometrium and kidney. FOXI1 encodes a transcription factor necessary for pendrin expression. Patients with PDS show a bilateral and severe-to-profound hearing loss, although some cases present with a slowly progressive and fluctuating course. Temporal bone abnormalities with enlargement of the vestibular aqueduct, alone or with Mondini dysplasia, are common. Goiter appears most frequently in the second decade of life with a range of variations in size, depending on the amount of iodide intake and the effect that the mutation causes in pendrin function in any individual patient. A standard thyroid hormone-replacement regimen should be given to PDS patients with hypothyroidism to re-establish euthyroidism and prevent or decrease goiter growth. Total or partial thyroidectomy is occasionally the treatment of choice. Hearing aids and proper educational programs should also be offered to patients.

Keywords::

• enlargement of vestibular aqueduct
• FOXI1 gene
• goiter
• hearing loss
• Pendred syndrome
• pendrin
• perchlorate discharge test
• SCL26A4 gene

Financial & competing interests disclosure

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.