Heredity hearing losses with delayed onset: mechanisms of expression.

Inherited hearing loss with a delayed onset is a feature of an intriguing group of disorders. The mechanisms whereby delayed hearing loss develops may be grouped as primary degenerative (abiotrophic) disorders, secondary degenerative disorders, dysgenerative disorders, and disorders of inappropriate response. Illustrative examples within these four groups are discussed. The difficulties in determining the preclinical latent state in inherited disorders are briefly outlined.