Waardenburg syndrome type 1 (WS1) is an autosomal dominant auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; and 'dystopia canthorum,' the lateral displacement of the ocular inner canthi. Clinical Variability of Waardenburg Syndrome Types 1-4 Waardenburg syndrome is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, including a white forelock and premature graying; pigmentary changes of the iris, such as heterochromia irides and brilliant blue eyes; and congenital sensorineural hearing loss. Waardenburg syndrome has been classified into 4 main phenotypes. WS type 1 is distinguished by the presence of dystopia canthorum. WS type 2 (WS2) is distinguished from type 1 by the absence of dystopia canthorum. WS type 3 (WS3) has dystopia canthorum and upper limb abnormalities. WS type 4 (WS4) also known as Waardenburg-Shah syndrome, has the additional feature of Hirschsprung disease. Waardenburg syndrome is genetically heterogeneous. WS1 and WS3 are both caused by mutation in the PAX3 gene. [From OMIM]