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SLC26A4 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SLC26A4 gene

The SLC26A4 gene provides instructions for producing the protein pendrin, which is essential for ion transport in the inner ear and thyroid gland.

Normal Function

The SLC26A4 gene provides instructions for making a protein called pendrin. This protein transports negatively charged particles (ions), including chloride, iodide, and bicarbonate, across cell membranes. Pendrin is produced in several organs and tissues, particularly the inner ear and thyroid gland.

The thyroid gland is a butterfly-shaped organ at the base of the neck that releases hormones to help regulate growth and the rate of chemical reactions in the body (metabolism). In the thyroid, pendrin is believed to transport iodide ions out of certain cells, which is necessary for the normal production of thyroid hormones.

In the inner ear, pendrin likely helps control the proper balance of ions, including chloride and bicarbonate. Maintaining these levels is important during the development of the inner ear and influences the shape of structures such as the cochlea (which processes sound) and the vestibular aqueduct (a bony canal connecting the inner ear to the skull). Pendrin is also found in the kidneys, liver, and lining of the airways.

Health Conditions Related to Genetic Changes

Pendred syndrome

Researchers have identified more than 150 mutations in the SLC26A4 gene in people with Pendred syndrome. This condition is characterized by:

  • Enlargement of the thyroid gland (goiter)
  • Hearing loss
  • Inner ear abnormalities, including an enlarged vestibular aqueduct

Genetic changes in SLC26A4 impair or eliminate the activity of pendrin, disrupting ion transport. In the thyroid, this prevents iodide from being available for hormone production, leading to compensatory thyroid enlargement. In the inner ear, the altered ion balance affects the development of the cochlea and vestibular aqueduct and leads to the loss of sensory cells required for hearing.

Other Related Conditions

Mutations in this gene are also associated with:

  • Nonsyndromic hearing loss
  • Congenital hypothyroidism (including thyroid hypoplasia)
  • Age-related hearing loss
  • Hashimoto's disease

It remains unclear whether these conditions are distinct disorders or part of a spectrum of related signs and symptoms.

Frequently Asked Questions

SLC26A4 mutations can lead to an enlarged thyroid gland (goiter) and, in some cases, hypothyroidism (underactive thyroid) due to impaired iodide transport. Thyroid function is monitored through regular blood tests measuring thyroid hormone levels (T3, T4) and thyroid-stimulating hormone (TSH). If hypothyroidism develops, it is treated with thyroid hormone replacement medication. The goiter itself may not require treatment unless it causes compressive symptoms or is cosmetically concerning.
The most common signs of Pendred syndrome include congenital (present from birth) or early-onset hearing loss, which can range from moderate to profound. Other key indicators are an enlarged thyroid gland (goiter), which may develop later in childhood or adolescence, and balance problems due to inner ear abnormalities. If a child exhibits unexplained hearing loss, especially if combined with a family history of similar issues or a noticeable swelling in the neck, a medical evaluation is recommended.
The hearing loss in Pendred syndrome is sensorineural and permanent. Management typically involves hearing aids, and for severe to profound hearing loss, cochlear implants are often very effective. Early intervention with amplification and speech therapy is crucial for language development. The long-term outlook for hearing and communication is generally good with appropriate management, allowing individuals to lead full lives.
If Pendred syndrome is suspected in your family, genetic testing for SLC26A4 mutations can confirm the diagnosis and identify carriers. This information is valuable for family planning. Options include prenatal diagnosis (testing during pregnancy) or preimplantation genetic diagnosis (PGD) in conjunction with in vitro fertilization to screen embryos. Genetic counseling is highly recommended to understand inheritance patterns, risks, and available reproductive choices.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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