rare, autosomal dominant disease with variable penetrance and several known clinical subtypes; characteristics may include depigmentation of the hair and skin, congenital deafness, heterochromia iridis, medial eyebrow hyperplasia, hypertrophy of the nasal root, and especially dystopia canthorum; the underlying cause may be defective development of the neural crest (neurocristopathy); may be closely related to piebaldism; Klein-Waardenburg Syndrome refers to a disorder that also includes upper limb abnormalities.