Speech-Language Pathologists' Responsibilities Toward Individuals Who Have Waardenburg Syndrome

Introduction

Waardenburg syndrome (WS) is a genetic condition that can produce facial, limb, and gastrointestinal anomalies along with varying degrees of sensorineural hearing loss. This syndrome was first identified in 1951, when a Dutch ophthalmologist reported the coexistence of pigment anomalies, eye anomalies, and hearing loss in some of his patients (Waardenburg, 1951). Since that time, four distinct types of WS have been identified based on phenotypic appearance and gene locus. WS affects an estimated 1 in 10,000 to 20,000 individuals in the general population (Read & Newton, 1997). Males and females are affected equally, as are all races and ethnic groups. WS is an interesting syndrome in that it is also found in animals such as splotch mice, horses, cats, and some specific breeds of dogs (Strain et al., 1992).

Some speech-language pathologists (SLPs) question their role in diagnosing and treating individuals with genetic syndromes or conditions, believing that these are solely the responsibilities of geneticists and physicians. Other SLPs have concerns about possible litigation resulting from referring individuals for genetic testing. Although diagnosis of specific genetic syndromes is not the responsibility of speech-language pathologists, it is the SLP's responsibility to be aware of genetic conditions that impact communication skills, to recognize patients who might be at risk for such conditions, to refer them for appropriate assessment and treatment, to treat the communication disorders associated with the syndrome, and to remain current in genetic information (Kahn, 2007). As Dr. Robert Shprintzen (1997) points out, SLPs are not qualified to render a genetic diagnosis, but they must, at the least, recognize that such a diagnosis may exist, and refer the patient for appropriate evaluation. This article describes SLP responsibilities and the major and minor characteristics of WS. It also suggests ways to recognize, refer, and treat individuals who may have this condition.

Responsibility #1: Recognizing Waardenburg Syndrome 

Waardenburg syndrome results from early errors by a complex group of genes that are responsible for production, development, and distribution of melanocytes. Melanocytes produce pigment (melanin)which provides color to eyes, skin, and hair, as well as to the stria vascularis of the cochlea. Some, though not all, of these genes have been identified, although exactly when and how they interact with other genes to regulate melanocyte development is currently unknown (Hou & Pavan, 2008). The unusual appearance of skin, hair, and eyes of someone with WS results from genetic errors in production and distribution of melanocytes, and this appearance is easily visible to even casual observers. What is not readily visible is the condition of pigment cells in the cochlea. Sensorineural hearing loss has been hypothesized to result from abnormal migration of melanocytes, subsequently affecting the development of the stria vascularis in the cochlea (Toriello, Reardon & Gorlin, 2004). Individuals with some forms of WS may also have additional serious anomalies including cleft palate, anophthalmia, limb defects, and Hirschsprung's disease. Because pigment loss causes some very striking physical anomalies of the head and face, one might expect that individuals with WS would be immediately identified at birth. This is far from the case. SLPs routinely perform oral-facial examinations, and consequently are able to observe and identify individuals at risk for WS and refer them to the appropriate professionals for diagnosis and treatment. To do this, the anomalies associated with WS must first be recognized.

Phenotypic Signs of Waardenburg Syndrome

Four types of WS have been identified based on phenotypic appearance, gene location, and pattern of inheritance. The only absolutely accurate way of diagnosing a syndrome is through genetic testing, but genetic testing is not yet available for all types of WS. In such cases observing an individual's physical characteristics is helpful in making referral decisions. Identifying a pattern of physical features in an individual is called phenotyping. These features can be internal as well as external, and can include mental states, and normal as well as abnormal, physical appearance. All individuals have a phenotype. Your phenotype, for example, might be that you are tall, have red hair, blue eyes, hypoplastic kidneys, and fair skin.

Each of the four types of WS has a specific phenotype. Some phenotypes are major and some are minor. "Minor," when speaking of phenotypic features, is a relative term. Such anomalies are "minor" only in comparison to the major, sometimes life-threatening conditions. The major and minor phenotypic features of each type of WS are summarized in Table 1 and major features and some minor features are discussed following Table 1. However, for additional information and color photos of WS phenotypes visit: www.units.muohio.edu/waardenburgsyndrome/