• The conditions of 70 patients with Usher's syndrome were studied by ophthalmic and neuro-otologic examinations. Two distinct clinical and presumed genetic types were discernible on the basis of differences in hearing impairment, vestibular sensitivity, and, to a lesser extent, deterioration in retinal photoreceptor function. Distinguishing these two types has relevance for both diagnosis and genetic counseling of patients with Usher's syndrome.
Fishman GA, Kumar A, Joseph ME, Torok N, Anderson RJ. Usher's SyndromeOphthalmic and Neuro-otologic Findings Suggesting Genetic Heterogeneity. Arch Ophthalmol. 1983;101(9):1367-1374. doi:10.1001/archopht.1983.01040020369005