Pathology of congenital deafness. Present status and future priorities.

The pathology of congenital hearing loss is as varied as the etiologies. Severe external ear anomalies, such as microtia, and middle ear defects have a significant incidence of accompanying inner ear aplasias, more often of the vestibular than of the cochlear end-organs. Classic inner ear aplasias are discussed, including Michel, Mondini, Alexander and Scheibe. A case illustrating close resemblance between a genetically induced Scheibe malformation and rubella inner ear deformities is present. A variety of ear disorders acquired during intrauterine or neonatal life, including cytomegalic inclusion disease, hypoxia, erythroblastosis fetalis and later-onset genetic disorders are also discussed. Illustrative case histories are presented as well as priorities for future investigations into the pathology of congenital and genetic hearing loss.