Overview, Causes, & Risk Factors Waardenburg syndrome is inherited as an autosomal dominant trait; only one parent has to pass on the gene for a child to be affected. There are four types of this syndrome. (Type 3 is known as Klein-Waardenburg syndrome; Type 4 is Waardenburg-Shah syndrome.) The multiple types of this syndrome result from mutations occurring in different genes. All types share two dominant features: hearing loss and partial albinism. The albinism is incomplete and may appear as a white forelock in an otherwise dark head of hair, very pale light-blue eyes, or two different coloured eyes (heterochromia irides). Affected individuals may also have wide separation of the inner corners of the eyes, a broad nasal bridge, and other color changes of the skin. Waardenburg syndrome affects about 1 in every 30,000 people. Almost 90% of patients have an affected parent but the symptoms in the parent can be quite different from those in the child. Description 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 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 WS 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 WS 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. Individuals with Waardenburg syndrome may have some or all of the traits of the syndrome. For example, a person with WS 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 WS as do changes in the skin and hair. On rare occasions, WS 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 WS. THE MAIN CHARACTERISTICS of Waardenburg syndrome (WS) include: a wide bridge of the nose; pigmentary disturbances such as two different colored eyes, white forelock and eyelashes and premature graying of the hair; and some degree of cochlear deafness. The disease was named for Petrus Johannes Waardenburg, a Dutch ophthalmologist (1886-1979) who was the first to notice that people with two different colored eyes frequently had hearing problems.   The several types of WS are inherited in dominant fashion, so researchers typically see families with several generations who have inherited one or more of the features.Type I of the disorder is characterized by displacement of the fold of the eyelid, while Type II does not include this feature, but instead has a higher frequency of deafness.   The discovery of the human gene that causes Type I WS came about after scientists speculated that the gene that causes 'splotch mice' (mice with a splotchy coat coloring) might be the same gene that causes WS in humans. They located the human gene to chromosome 2 and found it was the same as mouse Pax3. Pax3 is one of a family of eight mouse Pax genes that are involved in regulating embryonic development at the level of transcription.   With a mouse model to draw from, scientists are learning much about how Pax3 causes Waardenburg syndrome. Types of WS There are at least four types of Waardenburg syndrome. The most common types of WS identified by scientists are Type 1 and Type 2. The different types of physical characteristics a person has determines the type of WS. Persons who have an unusually wide space between the inner corners of their eyes have WS Type 1. Hearing impairments occur in about 20 percent of individuals with this type of Waardenburg syndrome. Persons who do not have a wide space between the inner corners of their eyes, but who have many other WS characteristics are described as having WS Type 2. About 50 percent of persons with WS Type 2 have a hearing impairment or are deaf. Cause 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 WS gene. Actually, there is a 50/50 chance that a child of an individual with WS will also have the syndrome.