Cochlear abnormalities in Alport's syndrome.

The cochleae of four patients with a diagnosis or suspicion of Alport's syndrome were examined by microdissection and surface preparations. Strial atrophy, found in all cases, was most pronounced in the middle and apical turns and mainly involved the inferior margin of the stria. Numerous vacuoles were seen in the spiral ligament behind the atrophic stria. The youngest patient, aged 16 years, who had little or no hearing loss, showed limited hair cell degeneration. The other two patients had severe hearing loss and extensive sensory cell loss of unusual distribution. In the specimens from the second patient, the extent of hair cell loss was fairly even throughout, but the loss of inner hair cells was far more severe than the loss of outer hair cells. In the third case, the loss of outer hair cells was most pronounced in the apical half of the cochlea. All of these specimens had only a mild secondary nerve degeneration. The specimens from the fourth patient were poorly preserved and showed only nerve degeneration.