Pendred

Pendred syndrome is a genetic disorder that causes early hearing loss in children and sometimes affects the thyroid gland. It is an autosomal recessive condition, meaning that an affected individual must inherit two copies of the mutated gene, one from each parent, to develop the syndrome.

Causes:

Pendred syndrome is primarily caused by mutations in the SLC26A4 gene, also known as PDS. This gene provides instructions for making a protein called pendrin, which is crucial for transporting chloride, iodide, and bicarbonate across cell membranes in the inner ear and thyroid gland. Mutations in SLC26A4 disrupt the normal function of pendrin, leading to the characteristic features of the syndrome.

Symptoms and Diagnosis:

The most common symptom of Pendred syndrome is sensorineural hearing loss, which is usually present at birth or develops in early childhood. The severity of hearing loss can vary from mild to profound. Individuals with Pendred syndrome may also experience balance problems (vestibular dysfunction) due to abnormalities in the inner ear.

Thyroid problems, such as goiter (enlargement of the thyroid gland), are also frequently observed in individuals with Pendred syndrome. However, thyroid function is often normal, or only mildly affected (e.g., subclinical hypothyroidism).

Diagnosis typically involves:

• Hearing tests (audiometry): To assess the extent and type of hearing loss.
• Temporal bone CT scan or MRI: To look for characteristic inner ear malformations, such as an enlarged vestibular aqueduct (EVA). An EVA is a bony channel that connects the inner ear to the inside of the skull. It is often enlarged in individuals with Pendred syndrome.
• Thyroid function tests: To evaluate thyroid hormone levels.
• Genetic testing: To confirm the diagnosis by identifying mutations in the SLC26A4 gene.

Treatment:

There is no cure for Pendred syndrome. Treatment focuses on managing the symptoms:

• Hearing aids or cochlear implants: To improve hearing.
• Speech therapy: To assist with language development.
• Thyroid hormone replacement therapy: If hypothyroidism is present.
• Management of balance problems: Through vestibular rehabilitation therapy, if necessary.

Prognosis:

The prognosis for individuals with Pendred syndrome varies depending on the severity of hearing loss and the presence of other health problems. With early diagnosis and appropriate management, individuals with Pendred syndrome can live full and productive lives. It is crucial for individuals diagnosed with Pendred syndrome to receive regular audiological and thyroid monitoring.