You Are Here >> Miscellaneous >> Waardenburg Syndrome
Waardenburg Syndrome
What is Waardenburg Syndrome?
Waardenburg Syndrome (WS) is an inherited disorder often characterized by varying degrees of hearing loss and changes in skin and hair pigmentation. The syndrome got its name from a Dutch eye doctor named Petrus Johannes Waardenburg who first noticed that people with differently colored eyes often had a hearing impairment. He went on to study over a thousand individuals in deaf families and found that some of them had certain physical characteristics in common.
One commonly observed characteristic of Waardenburg Syndrome (WS) is two differently colored eyes. One eye is usually brown and the other blue. Sometimes, one eye has two different colors. Other individuals with Waardenburg Syndrome may have unusually brilliant blue eyes.
People with Waardenburg Syndrome may also have distinctive hair coloring, such as a patch of white hair or premature gray hair as early as age 12. Other possible physical features include a wide space between the inner corners of eyes called a broad nasal root. In addition persons with Waardenburg Syndrome may have low frontal hairline and their eyebrows may connect. The levels of hearing loss associated with the syndrome can vary from moderate to profound.
People with Waardenburg Syndrome may have some or all of the traits of the syndrome. For example, a person with Waardenburg Syndrome may have a white forelock, a patch of white hair near the forehead, and no hearing impairment. Others may have white patches of skin and severe hearing impairment. The severity of the hearing impairment varies among individuals with Waardenburg Syndrome as do changes in the skin and hair.
On rare occasions, Waardenburg Syndrome has been associated with other conditions that are present at birth, such as intestinal disorders, elevation of the shoulder blade, and disorders of the spine. A facial abnormality, known as cleft lip and/or palate, also has been associated with Waardenburg Syndrome.
Types of Waardenburg Syndrome
There are at least four types of Waardenburg Syndrome. The most common types of Waardenburg Syndrome identified by scientists are Type 1 and Type 2. The different types of physical characteristics a person has determines the type of Waardenburg Syndrome.
- Type 1 - People who have an unusually wide space between the inner corners of their eyes. Hearing impairments occur in about 20 percent of individuals with this type of Waardenburg Syndrome.
- Type 2 - People who do not have a wide space between the inner corners of their eyes, but who have many other Waardenburg Syndrome characteristics. About 50 percent of individuals with Waardenburg Syndrome Type 2 have a hearing impairment or are deaf.
Causes of Waardenburg Syndrome
As a genetic disorder, Waardenburg Syndrome is passed down from parent to child much like hair color, blood type, or other physical traits. A child receives genetic material from each parent. Because Waardenburg Syndrome is a dominant condition, a child usually inherits the syndrome from just one parent who has the malfunctioning Waardenburg Syndrome gene. Actually, there is a 50/50 chance that a child of an individual with Waardenburg Syndrome will also have the syndrome.
Research Studies of Waardenburg Syndrome
Scientists have identified and located four different genes for Waardenburg Syndrome:
- PAX3 - Waardenburg Syndrome type 1 and 3 have been associated with mutations in the PAX3 gene. The PAX3 gene is located on chromosome 2 and controls some aspects of the development of the face and inner ear.
- MITF - Waardenburg Syndrome type 2 with the MITF gene. The MITF gene is found on chromosome 3. It also controls the development of the ear and hearing.
- EDNRB and EDN3 - Waardenburg Syndrome type 4 with the EDNRB and EDN3 genes.
While scientists are studying all of these genes, currently, the most information is available on the PAX3 and MITF genes and their role in Waardenburg Syndrome.
Scientists are now studying these genes to better understand how they operate in controlling the normal growth of the ear and the development of hearing. This information will help scientists understand why persons with Waardenburg Syndrome sometimes develop hearing problems.
For more information, contact the NIDCD Information Clearinghouse @:
National Institute on Deafness and Other Communication Disorders (NIDCD)
National Institutes of Health
31 Center Drive, MSC 2320
Bethesda, Maryland USA 20892-2320
E-mail: nidcdinfo@nidcd.nih.gov
References:
1) National Institute on Deafness and Other Communication Disorders (NIDCD) - National Institutes of Health (NIH) - NIH Pub. No. 91-3260 - March 1999 - www.nidcd.nih.gov
This summary is a general overview about the topic discussed and does not include all the facts, or include everything there is to know about any medicine and/or products mentioned. Do not use any medicine and/or products without first talking to your doctor. Possible side effects of medications, other than those listed, may occur. Full Disclaimer & General Safety Advisory