[Personal experience with genetic study of the hearing-impaired].

In 1988-1990 the authors examined on account of impaired hearing in the family 78 families, which were divided into two groups. The first group comprises 48 families of actively invited pupils from schools with children with impaired hearing in Prague, the second group comprises 30 families examined in the framework of common counselling and consultation services. On the first group a genetic aetiology of the disorder was revealed in 75% and in the second group in 73.