My watch list
my.bionity.com  
Login  

Waardenburg syndrome



Waardenburg syndrome
Classification & external resources
ICD-10 E70.3 (ILDS E70.32)
ICD-9 270.2
DiseasesDB 14021 33475
MedlinePlus 001428
eMedicine ped/2422  derm/690
MeSH D014849

Waardenburg syndrome is a rare genetic disorder most often characterized by varying degrees of deafness, minor defects in structures arising from the neural crest, and pigmentation anomalies.

Contents

Eponyms and classification

It is named after Dutch ophthalmologist Petrus Johannes Waardenburg (1886-1979), who first defined it in 1951.[1] [2] The condition he described is now categorized as WS1.

WS2 was identified in 1971, to describe cases where "dystopia canthorum" did not present.[3] WS2 is now split into subtypes, based upon the gene responsible.

Other types have been identified, but they are less common.

Subtypes of the syndrome are traceable to different genetic variations:

Type OMIM Gene Locus Also known as
Type I, WS1 193500 PAX3 - "paired box 3" (PAX3) 2q35 -
Type IIa, WS2A (originally WS2) 193510 MITF -"microphthalmia-associated transcription factor" 3p14.1-p12.3 -
Type IIb, WS2B 600193 WS2B 1p21-p13.3 -
Type IIc, WS2C 606662 WS2C 8p23 -
Type IId, WS2D (very rare) 608890 SNAI2 8q11 -
Type III, WS3 148820 PAX3 - "paired box gene 3" 2q35 Klein-Waardenburg syndrome
Type IV, WS4 277580 EDNRB - "endothelin-B receptor"
EDN3 - its ligand, "endothelin-3"
SOX10 - "SRY-related HMG-box gene 10"
22q13, 20q13.2-q13.3, 22q13 Waardenberg-Hirschsprung disease, Waardenburg-Shah syndrome

There are several other names used. These include Klein-Waardenburg syndrome, Mende's syndrome II, Van der Hoeve-Halbertsma-Waardenburg syndrome, Ptosis-Epicanthus syndrome, Van der Hoeve-Halbertsma-Gualdi syndrome, Waardenburg type Pierpont[4], Van der Hoeve-Waardenburg-Klein syndrome, Waardenburg's syndrome II, and Vogt’s syndrome.

Incidence

Types I and II are the most common types of the syndrome, whereas types III and IV are rare. Overall, the syndrome affects perhaps 1 in 15,000 people. About 1 in 30 students in schools for the deaf have Waardenburg syndrome. All races and both sexes are affected equally. The highly variable presentation of the syndrome makes it difficult to arrive at precise figures for its prevalence.

Symptoms

Symptoms vary from one type of the syndrome to another and from one patient to another, but they include:

  • Very pale or brilliantly blue eyes, eyes of two different colors (complete heterochromia), or eyes with one iris having two different colours (sectoral heterochromia);
  • A forelock of white hair (poliosis), or premature graying of the hair;
  • Wide-set eyes (hypertelorism) due to a prominent, broad nasal root (dystopia canthorum—particularly associated with type I);
  • Moderate to profound hearing impairment (higher frequency associated with type II); and
  • A low hairline and eyebrows that touch in the middle.
  • Patches of white pigmentation on the skin have been observed in some people. Sometimes, abnormalities of the arms, associated with type III, have been observed.
  • Type IV may include neurologic manifestations.

Waardenburg syndrome has also been associated with a variety of other congenital disorders, such as intestinal and spinal defects, elevation of the scapula, and cleft lip and palate.

Inheritance

This condition is usually inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. A small percentage of cases result from new mutations in the gene; these cases occur in people with no history of the disorder in their family.

Some cases of type II and type IV Waardenburg syndrome appear to have an autosomal recessive pattern of inheritance, which means two copies of the gene must be altered for a person to be affected by the disorder. Most often, the parents of a child with an autosomal recessive disorder are not affected but are carriers of one copy of the altered gene.

Treatment

There is currently no treatment or cure for Waardenburg syndrome. The symptom most likely to be of practical importance is deafness, and this is treated as any other irreversible deafness would be. In marked cases there may be cosmetic issues. Other abnormalities (neurological, structural) associated with the syndrome are treated symptomatically.

In animals

Waardenburg syndrome is known to occur in ferrets. The affected animal will usually have a small white stripe along the top of its head and a somewhat, although barely noticeably, flatter skull than normal ferrets. As a ferret's sense of hearing is poor to begin with it is not easily noticeable except for when the affected animal does not react to loud noises that non-affected ones will respond to. As the disorder is easily spread to offspring, the affected animal will not be used for breeding, although it may still be neutered and sold as a pet.

References

  1. ^ Waardenburg PJ (1951) "A new syndrome combining developmental anomalies of the eyelids, eyebrows and nose root with pigmentary defects of the iris and head hair and with congenital deafness". Am J Hum Genet 1951; 3: 195-253.
  2. ^ doctor/1012 at Who Named It
  3. ^ Arias S (1971). "Genetic heterogeneity in the Waardenburg syndrome". Birth Defects Orig. Artic. Ser. 07 (4): 87-101. PMID 5006208.
  4. ^ http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=3441
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Waardenburg_syndrome". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE