Waardenburg syndrome with a fixed dilated pupil.

An unusual case of Waardenburg syndrome associated with a detailed and fixed pupil of the lighter eye is described. Pharmacological investigations were performed to localise the site of the pupillary lesion. A lack of cholinergic reactivity was demonstrated, possibly due to congenital agenesis of the sphincter pupillae. Sympathetic activity was not impaired. Spiral ganglion agenesis and midline congenital anomalies are common features in Waardenburg syndrome. These lesions as well as the fixed dilated pupil might be due to an embryonal inductive failure.