Waardenburg Syndrome, Type 4

Clinical Characteristics

Ocular Features:

The skin and ocular pigmentary changes and the sensorineural hearing loss in type 4 Waardenburg syndrome resembles that of other types. Patients, however, usually lack synophrys and dystopia canthorum.

Systemic Features:

Type 4 Waardenburg syndrome is largely similar to other types except that many patients also have Hirschsprung disease.

Genetics

Both autosomal dominant and recessive inheritance have been reported for type 4 Waardenburg syndrome. Both heterozygous and homozygous mutations in the EDNRB [1] (endothelin-B receptor) gene (13q22) occur in patients. The aganglionic megacolon feature may be dose sensitive since homozygotes have been reported to have a 74% chance of developing Hirschsprung disease while only 21% of heterozygotes do so.

Types 4A (277580 [2]) and 4B (613265 [3]) are both caused by mutations in the EDNRB [1] gene, and type 4C (613266 [4]) results from a mutation in the SOX10 [5] gene. Waardenburg syndrome WS2E is allelic to type 4C. This is an example of genetic heterogeneity both within the main types and within the subtypes.

Treatment

Treatment Options:

No ocular treatment is necessary but assistive hearing devices can be beneficial.

References

Article Title:

Review and update of mutations causing Waardenburg syndrome [6]

Pingault V, Ente D, Dastot-Le Moal F, Goossens M, Marlin S, Bondurand N. Review and update of mutations causing Waardenburg syndrome. Hum Mutat. 2010 Apr;31(4):391-406. Review.

PubMed ID:

20127975

Waardenburg syndrome [7]

Read AP, Newton VE. Waardenburg syndrome. J Med Genet. 1997 Aug;34(8):656-65. Review.

PubMed ID:

9279758

Mutation of the endothelin-receptor B gene in Waardenburg-Hirschsprung disease [8]

Atti?(c) T, Till M, Pelet A, Amiel J, Edery P, Boutrand L, Munnich A, Lyonnet S. Mutation of the endothelin-receptor B gene in Waardenburg-Hirschsprung disease. Hum Mol Genet. 1995 Dec;4(12):2407-9.

PubMed ID:

8634719