Waardenburg syndrome type 3 is an auditory-pigmentary syndrome characterized by pigmentary abnormalities of the hair, skin, and eyes; congenital sensorineural hearing loss; presence of 'dystopia canthorum,' the lateral displacement of the ocular inner canthi; and upper limb abnormalities (reviews by Read and Newton, 1997 and Pingault et al., 2010). WS type 3 is also referred to as 'Klein-Waardenburg syndrome' (Gorlin et al., 1976). Clinical Variability of Waardenburg Syndrome Types 1-4 Waardenburg syndrome has been classified into 4 main phenotypes. Type I Waardenburg syndrome (WS1; 193500) is characterized by pigmentary abnormalities of the hair, including a white forelock and premature graying; pigmentary changes of the iris, such as heterochromia iridis and brilliant blue eyes; congenital sensorineural hearing loss; and 'dystopia canthorum.' WS type II (WS2) is distinguished from type I by the absence of dystopia canthorum. WS type III has dystopia canthorum and is distinguished by the presence of upper limb abnormalities. WS type IV (WS4; 277580), also known as Waardenburg-Shah syndrome, has the additional feature of Hirschsprung disease (reviews by Read and Newton, 1997 and Pingault et al., 2010).