[The incidence of Usher's syndrome and its clinical types]

We investigated the incidence and types of Usher's syndrome in normal, hearing handicapped, and visually handicapped individuals.

Usher's syndrome was investigated among 115,000 healthy young males who were screened prior to military service, among patients in whom retinitis pigmentosa was diagnosed at the Ophthalmology Department of Ege University, and among the students of Izmir Tülay Aktaş School for the Deaf and Izmir Aşik Veysel School for the Blind. Patients with retinitis pigmentosa were evaluated by comprehensive history taking, pedigree drawing, ophthalmologic and otolaryngologic examinations, audiovestibular tests, and electroretinography.

Usher's syndrome was detected in only one subject among candidates of military service, in six subjects among 386 students of School for the Deaf, and in three cases among 30 patients with retinitis pigmentosa. None of the students of the School for the Blind had Usher's syndrome. Screening of the patients' family members revealed eight families with Usher's syndrome, yielding a total of 15 patients. Consanguinity was documented in five families. Eleven patients (73%) had type 1 and four patients (27%) had type 2 disease. Type 3 disease was not encountered.

Investigation of Usher's syndrome in patients with hearing loss and impaired vision in the dark will promote better rehabilitation and monitoring of these patients. Consanguinity should be sought in affected individuals.