The association of Waardenburg syndrome and Hirschsprung disease. Patients present in the neonatal period with pigmentary anomalies (including white forelock, white eyebrows and eyelashes, white skin patches and pigmentary anomalies of the irides) in association with intestinal obstruction. Neurosensorial deafness is common and early, and may be unilateral. Psychomotor development is normal. Three disease-causing genes have been identified so far: EDNRB (13q22.3) encoding the endothelin-B receptor, EDN3 (20q13.32) encoding an endothelin receptor ligand and SOX10 (22q13.1) encoding the SOX10 transcription factor.