Table 1.

Classifications of Waardenburg syndrome.

	Clinical manifestations	The incidence rate of SNHL	Genetic mutation
Type 1	Dystopia canthorum, white forelock, white eyelashes, leukoderma, heterochromia iridis	60%	PAX3
Type 2	The absence of dystopia canthorum	90%	MITF, WS2B, WS3B   EDNRB, EDN3, SOX10   SNAI2
Type 3	Type 1 + upper limb abnormalities	60%	PAX3
Type 4	Type 2 + Hirschsprung's disease	90%	EDNRB, EDN3, SOX10