NIDCD Fact Sheet

Pendred Syndrome 

u.s. department of health & human services ∙ national institutes of health ∙ National Institute on Deafness and Other Communication Disorders hearing balance

What is Pendred syndrome?

Pendred syndrome is a genetic disorder that causes early 

hearing loss in children. It also can affect the thyroid 

gland and sometimes may affect a person’s balance. 

The syndrome is named after Vaughan Pendred, the 

physician who first described individuals with 

the disorder. 

Children who are born with Pendred syndrome may 

begin to lose their hearing at birth or by the time they 

are three years old. The hearing loss is progressive, 

which means that a child will have less hearing over 

time. Some individuals may become totally deaf. 

The loss of hearing often happens suddenly and in 

stages. Sometimes, after a sudden decrease in hearing, 

a person’s hearing will nearly return to its previous level. 

Almost all people with Pendred syndrome have bilateral 

hearing loss, or hearing loss in both ears. The hearing 

loss often is greater in one ear than in the other. 

How does Pendred syndrome affect 

other parts of the body?

Pendred syndrome can affect the thyroid by causing it to 

grow too large. An enlarged thyroid gland also is called 

a goiter. The thyroid is a small, butterfly-shaped gland in 

the front of your neck, just above your collarbones. The 

thyroid plays a major role in how your body uses energy 

from food. In children, the thyroid is important for 

normal growth and development. Children with Pendred 

syndrome, however, rarely have problems growing and 

developing properly even if their thyroid is affected. 

Roughly 60 percent of individuals with Pendred 

syndrome will develop a goiter in their lifetime. Most 

people with Pendred syndrome are in their teens 

or twenties before they develop a goiter. If a goiter 

becomes large, a person may have problems breathing 

and swallowing. A health professional is needed to 

check a person’s goiter over time and decide what 

treatment is necessary. 

Pendred syndrome also may affect the vestibular 

system, which controls balance. About 40 percent of 

individuals with Pendred syndrome will show some 

vestibular weakness when their balance system is tested. 

However, the brain is very good at making up for a 

weak vestibular system, and most children and adults 

with Pendred syndrome do not have a problem with 

their balance or have difficulty doing routine tasks. 

Some babies with Pendred syndrome may start walking 

later than other babies. It is not known why some 

individuals with Pendred syndrome develop a goiter or 

have balance problems and others do not. 

What causes Pendred syndrome?

Pendred syndrome can be caused by changes, or 

mutations, to a gene known as SLC26A4 (also referred 

to as the PDS gene) on chromosome 7. Because it is 

a recessive trait, a child needs to inherit two mutated 

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NIDCD Fact Sheet

Pendred Syndrome

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SLC26A4 genes—one from each parent—to have 

Pendred syndrome. The child’s parents do not need to 

have Pendred syndrome to be a carrier of a mutation in 

the SLC26A4 gene. 

Couples who are concerned that they might be able to 

pass Pendred syndrome on to their children may seek 

genetic testing. A possible sign that a person may be a 

carrier of a mutated SLC26A4 gene is a family history 

of early hearing loss. Another sign is a family member 

who has both a goiter and hearing loss. A mutation in 

the SLC26A4 gene can be determined by genetic testing 

that uses a blood sample.

The decision to have a genetic test is complex. Most 

people receive assistance from a genetic counselor 

trained to help them weigh the medical, emotional, and 

ethical considerations. A genetic counselor is a health 

professional who provides information and support to 

individuals and families who have a genetic disease or 

who are at risk for such a disease. 

How is Pendred syndrome diagnosed?

A physician called an otolaryngologist or a clinical 

geneticist will consider a person’s hearing, inner ear 

structures, and sometimes the thyroid in diagnosing 

Pendred syndrome. The specialist will evaluate the 

timing, amount, and pattern of hearing loss. He or 

she will ask questions such as “When did the hearing 

loss start?”, “Has it worsened over time?”, and “Did 

it happen suddenly or in stages?” Early hearing loss is 

one of the most common characteristics of Pendred 

syndrome; however, this symptom alone does not mean 

a child has the condition.

The specialist uses inner ear imaging techniques 

known as magnetic resonance imaging (MRI) or 

computed tomography (CT or CAT) to look for two key 

characteristics of Pendred syndrome. One characteristic 

might be a cochlea with too few turns. The cochlea is 

the spiral-shaped part of the inner ear that converts 

sound into electrical signals that are sent to the brain. 

A healthy cochlea has two-and-a-half turns, but the 

cochlea of a person with Pendred syndrome may have 

only one-and-a-half turns. 

A second characteristic of Pendred syndrome is 

enlarged vestibular aqueducts (see figure on page 

1). The vestibular aqueduct is a bony canal that runs 

from the vestibule (a part of the inner ear between the 

cochlea and the semicircular canals) to the inside of 

the skull. Inside the vestibular aqueduct is a fluid-filled 

tube called the endolymphatic duct, which ends at a 

balloon-shaped endolymphatic sac. When the vestibular 

aqueduct is enlarged, the endolymphatic duct and sac 

grow large with excess fluid in comparison to their 

normal sizes. The function of the vestibular aqueduct is 

not well understood. 

When screening for Pendred syndrome, it is not 

recommended to test the blood for thyroid hormone 

because the amount usually is the same whether 

someone has Pendred syndrome or not. Some people 

may receive a “perchlorate washout test,” a test 

that determines whether the thyroid is functioning 

properly. Although this test is probably the best test 

for determining thyroid function in Pendred syndrome, 

it is not used often and may be replaced by genetic 

testing. Individuals who have a goiter may be referred 

to an endocrinologist, a doctor who specializes in 

glandular disorders, to determine whether the goiter is 

due to Pendred syndrome or to another cause. Goiter 

is a common feature of Pendred syndrome, but many 

individuals who develop a goiter do not have Pendred 

syndrome. Conversely, many people who have Pendred 

syndrome never develop a goiter. 

How common is Pendred syndrome?

Scientists estimate that about two to three children out 

of every 1,000 have early hearing loss, and about half 

of these cases are inherited. The SLC26A4 gene, which 

causes Pendred syndrome, accounts for about five to ten 

percent of hereditary hearing loss. As researchers gain 

more insight about the syndrome and its features, they 

hope to improve doctors’ ability to detect and diagnose 

the disorder in people.
Can Pendred syndrome be treated?

Treatment options are available for individuals with 

Pendred syndrome. Because the syndrome is inherited 

and can involve thyroid and balance problems, many 

specialists may be involved in treatment. The treatment 

team may include a primary care physician, an 

audiologist, an endocrinologist, a clinical geneticist, a 

genetic counselor, an otolaryngologist, and a speechlanguage pathologist.

To reduce the likelihood of progression of hearing 

loss, individuals with Pendred syndrome should avoid 

contact sports that might lead to head injury; wear head 

protection when engaged in activities that might lead to 

head injury (such as bicycle riding or skiing); and avoid 

situations that can lead to barotrauma (extreme, rapid 

changes in pressure), such as scuba diving or hyperbaric 

oxygen treatment.

Pendred syndrome cannot be cured. However, the 

medical team can help parents and individuals make 

informed choices about treatment options. They also 

can help them prepare for increased hearing loss and 

other possible long-term consequences of the syndrome.

Children with Pendred syndrome should start 

early treatment to learn skills that will help them 

communicate, such as learning sign language or cued 

speech or how to use a hearing aid. Most individuals 

with Pendred syndrome will have hearing loss significant 

enough to be considered eligible for a cochlear implant. 

A cochlear implant is an electronic device that is 

surgically inserted into the cochlea. A cochlear implant 

does not restore or create normal hearing. Instead, a 

cochlear implant helps a person develop a new way of 

understanding speech. Children over 12 months of age 

as well as adults are eligible to receive an implant. (For 

more information, see the National Institute on Deafness 

and Other Communication Disorders [NIDCD] fact sheet 

entitled “Cochlear Implants.”)

Individuals with Pendred syndrome who develop a goiter 

need to have it checked regularly. The goiter in Pendred 

syndrome is unusual because the thyroid is making the 

right amount of thyroid hormone, but it is growing in 

size. Such a goiter often is called a euthyroid goiter. For 

more information on the treatment of goiters, contact 

the National Institute of Diabetes and Digestive and 

Kidney Diseases (NIDDK) at www.niddk.nih.gov. 

What research is being conducted?

NIDCD has been working to understand hearing 

loss caused by inherited syndromes such as Pendred 

syndrome as well as from other causes. Researchers also 

are looking carefully at the characteristics of the disorder 

and how the syndrome might cause problems in such 

different parts of the body as the thyroid and inner ear.

Scientists continue to study the genetic basis of Pendred 

syndrome. The protein that the SLC26A4 gene encodes, 

called pendrin, is found in the inner ear, kidney, and 

thyroid gland. Researchers have identified more than 90 

deafness-causing mutations or alterations of this gene. 

Scientists have altered the gene in mice so that the mice 

have an abnormal SLC26A4 gene. The study of these 

mice is providing information on how the abnormal 

gene affects the form and function of different parts 

of the body. For example, by studying the inner ears of 

mice with SLC26A4 mutations, scientists now realize 

that the enlarged vestibular aqueduct associated with 

Pendred syndrome is not caused by a sudden stop in 

the normal development of the ear. Studies such as 

this are important because they help scientists rule out 

some causes of a disorder while helping to identify 

areas needing more research. Eventually, researchers are 

hopeful that these studies will lead to therapies that can 

target the basic causes of the condition.

Where can I get more information?

NIDCD maintains a directory of organizations that can 

answer questions and provide printed or electronic 

information on Pendred syndrome. Please see the list of 

organizations at www.nidcd.nih.gov/directory.

Improving the lives of people who have communication disorders
Use the following keywords to help you search for 

organizations that are relevant to Pendred syndrome:

• Hereditary hearing loss

• Genetic diseases/disorders

• Early identification of deafness in children

For more information, additional addresses and phone 

numbers, or a printed list of organizations, contact:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

Fax: (301) 770-8977

E-mail: nidcdinfo@nidcd.nih.gov

NIDCD supports and conducts research and research training on the 

normal and disordered processes of hearing, balance, smell, taste, 

voice, speech, and language and provides health information, based 

upon scientific discovery, to the public.

NIDCD Fact Sheet: Pendred Syndrome

NIH Publication No. 06-5875

Updated April 2007

For more information, contact:

NIDCD Information Clearinghouse

1 Communication Avenue

Bethesda, MD 20892-3456

Toll-free Voice: (800) 241-1044

Toll-free TTY: (800) 241-1055

Fax: (301) 770-8977 

E-mail: nidcdinfo@nidcd.nih.gov

Internet: www.nidcd.nih.gov

The NIDCD Information Clearinghouse is a service of the 

National Institute on Deafness and Other Communication 

Disorders, National Institutes of Health, U.S. Department 

of Health and Human Services.

hearing, balancesmell, tastevoice, speech, language