Physiopathological investigations in a family with a history of unilateral hereditary deafness.

We examined several members of the same family with unilateral sensorineural hearing loss. The defect showed dominant inheritance. Clinical examination and auditory tests, including high-definition audiogram and otoacoustic emission recording, were done to characterize the physiopathological process of hearing loss, and to investigate possible asymptomatic auditory features in the normal ear of affected subjects and nonaffected siblings. Hypotheses as to the underlying mechanisms are discussed, eg, variable expression of bilateral isolated hereditary deafness, incomplete Klein-Waardenburg syndrome with stria vascularis anomalies and highly variable gene expression, or unilateral cochlear aplasia. The phenomenon may also be related to the delayed progressive unilateral loss in patients with bilateral hereditary deafness, involving perhaps unilateral vascular disorders or a genetically induced degeneration of cochlear cells or auditory neurons.