Cochleosaccular Degeneration With Progressive Cataracts

Clinical Features

Nadol and Burgess (1982) described a family in which progressive deafness due to cochleosaccular degeneration of the inner ear was associated with progressive cataracts. The proband died at the age of 65 years of multiple injuries sustained in a motorcycle accident. He had congenital cataract in the right eye and subsequently developed a cataract in his left eye; cataract extractions were performed at the age of about 42. Hearing loss was first noted at the age of 26. He developed difficulty with balance at age 58, coincident with rapid deterioration in hearing. Staggering gait suggesting that he was drunk was noted. The association of deafness and cataracts with the same natural history as that in the proband was documented in at least 6 members of 5 different sibships in 4 generations with 3 instances of male-to-male transmission of the full syndrome. Progressive deafness was said to have been present in 9 other individuals although the presence of cataracts was incompletely determined. Guala et al. (1992) observed what appeared to be the same condition in 8 members of 4 generations. There was again no instance of male-to-male transmission.

Other Features

Description of cochleosaccular dysplasia of the inner ear in congenitally deaf patients is attributed to Scheibe (1892). Inner ear pathologic changes limited to the cochlea and saccule have been described as the cause of both congenital deafness and progressive postnatal sensorineural hearing loss. The disorder should be called cochleosaccular dysplasia when it refers to disordered development causing congenital deafness, and cochleosaccular degeneration when it refers to postnatal deterioration of a normally developed inner ear causing progressive sensorineural hearing loss. Cochleosaccular dysplasia was the abnormality observed in the syndrome of deafness with diverticula of the small bowel and progressive sensory neuropathy (221400).

Lalwani et al. (1999) mapped a locus for nonsyndromic hereditary hearing impairment, DFNA17 (603622), to chromosome 22 and pointed out, on the basis of histologic examination of the temporal bone in the proband, that this locus represents a gene for cochleosaccular degeneration.