[Forms of monosymptomatic hereditary sensorineural hearing loss and deafness in the Leipzig area]

More than one third of all sensorineural hearing loss and deafness has a genetic basis. Syndromes are already clinically distinguishable from monosymptomatic forms, but even the latter represent a heterogeneous group of diseases, which differ in mode of transmission, audiometric features of the hearing loss and possible progredience of the symptoms. Till now only audiometric and genealogical methods have been available for diagnosis. So far serological and cytogenetical studies have given no results and molecular-genetic investigations have only given results for some very rare syndromes. To help affected families and to prepare molecular-genetic studies we examined all patients at our hospital who suffer from a sensorineural hearing impairment for the onset of a monogeneous mode of transmission. Altogether we could find 39 stricken kins, 15 of them with autosomal-dominant, 16 with autosomal-recessive and 8 with an unclear mode of transmission. We registered anamnestically 1548 persons, from these 171 were suffering from hereditary hearing impairment. We were able to examine 117 of the affected persons. Seven typical audiometric features could be found. Including mode of transmission and possible progredience even 17 forms can be found. This represents a higher number of monosymptomatic forms of hereditary sensorineural hearing loss than described in the literature. It emphasizes that the main obstacle hindering future genotypical diagnosis will be the extreme high heterogenity.