What is Pendred Syndrome: Causes, Symptoms, Treatment, Prognosis

Pendred Syndrome is a genetic condition that can affect the thyroid gland and hearing function in children. This article deals with details of Pendred Syndrome, its causes, symptoms and treatment.

Pendred Syndrome is a genetic pathological condition which is caused by mutation in gene SLC26A4 in chromosome 7. The mutation in this gene causes progressive hearing loss in children and affects the thyroid gland resulting in goiter. In some cases Pendred Syndrome also affects the balance of a child.^[1]

The symptoms of Pendred Syndrome start becoming apparent by the time the child is about 2 to 3 years of age. By this time, the child starts to have hearing problems which worsens with time and advances to hearing loss. Complete hearing loss may be of sudden onset although some children may regain some of the hearing back. The hearing loss due to Pendred Syndrome is always bilateral (hearing loss is affected in both the ears) although the severity of the hearing loss in both the ears may vary.^[2]

Researchers believe that about 60% of cases of bilateral hearing loss are due to genetic causes and the remaining 40% due to other causes.^[3]

A detailed history of the child in regard to when the hearing loss started and whether there are any anatomical abnormalities in the ears can tell a physician whether the child has Pendred Syndrome or the hearing loss is being caused by some other source.

As stated, the main cause of Pendred Syndrome is a mutation in gene SLC26A4 in chromosome 7. This condition is an autosomal recessive trait which means that the child needs to inherit a copy of the defective gene from each parent to have this condition. Couples who feel they are at risk of being carriers of Pendred Syndrome and may pass it on to their children may seek genetic counseling to check whether they abnormalities in this gene.

To know whether a couple is at risk of being a carrier of Pendred Syndrome is having a family history of hearing loss at a young age from either side of the family. While the main causes of Pendred Syndrome are related to genetics, there have been cases where a child was diagnosed with Pendred Syndrome without any prior family history of this disorder known.^[4]

Some of the symptoms of Pendred Syndrome are:

• Presence of sensorineural hearing when the baby is born
• Changes in the inner ear
• Thyroid enlargement
• Vestibular dysfunction resulting in balance problems^[5]

As soon as a parent recognizes that their child has a problem with hearing then the first thing to do is to take the child to a skilled otolaryngologist to find about the etiology of the hearing loss. In the course of finding out an etiology for the hearing loss of the child, the doctor will take a detailed history of the child. Questions like when the hearing loss was first observed and whether the hearing loss was progressive or was it of a sudden onset are asked. Based on the answers given by the parents, the doctor may look at various pathologies that can cause such symptoms as Pendred Syndrome is not the only disease condition that causes hearing loss at birth.

If on examination, the thyroid is found to be enlarged then this coupled with the hearing loss may point towards the possibility of Pendred Syndrome. If this condition is suspected, then more tests will be done in order to confirm the diagnosis of Pendred Syndrome.

The best method for confirming the diagnosis of Pendred Syndrome is an MRI or CT scan of the inner ear to look for characteristic features of Pendred Syndrome. Normally, a cochlea has about 2.5 turns while in a child with Pendred Syndrome there will be less turns in the cochlea than this. Another important characteristic for Pendred Syndrome is an abnormal vestibular aqueduct which is important for balance and any abnormality in this will cause balance problems which is one of the significant symptoms of Pendred Syndrome. If these two abnormalities are positive then a diagnosis of Pendred Syndrome is confirmed.^[7]

There is at present no complete treatment of Pendred Syndrome but the symptoms that it produces can be treated. Since Pendred Syndrome involves more than one body system involved hence the treatment approach is also multidisciplinary involving ENT, neurologist, endocrinologist, and speech therapist.

Hence, the focus on symptomatic treatment of Pendred Syndrome.

Hearing loss which is the primary symptoms of Pendred Syndrome can be controlled with hearing aids which may improve hearing to certain extent.

Additionally, children with Pendred Syndrome should be taught sign language so that they put their though across without any problems.

Another potential treatment for Pendred Syndrome is a cochlear implant. In a cochlear implant, a device is inserted into the cochlea. While this device does not restore normal hearing, it bypasses the diseased components of the ear and sends signals to the brain directly and produces some sense of hearing and hence the child may be able to heart to some extent.

For thyroid problems due to Pendred Syndrome, the child will have to be observed and monitored closely with regular checks of thyroid function and if any abnormalities are found appropriate treatments are given.

The role of a speech therapist is also important in treatment of Pendred Syndrome as they may teach the child sign language and other measures to make the child as independent as possible.^[8]

Pendred Syndrome does not affect the life expectancy of a child in any way, hence the prognosis of Pendred Syndrome is good. Children with this condition lead normal lives other than the hearing and balance difficulties that can be managed with different ways of treatment of Pendred Syndrome. Cochlear implants and sign language improve the quality of life of a child significantly despite Pendred Syndrome.^[9]

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