Detection of normal-hearing carriers of the gene for the autosomal dominant progressive sensorineural hearing loss.

Normal-hearing carriers of genes for autosomal dominant progressive sensorineural hypacusis can apparently be detected in families where this hearing disorder appears. In a group of 32 persons from four families, 13 carriers of the gene with subjectively good hearing and normal audiometric curves were found. Due to the pathologically elevated threshold of stapedial reflexes and in some cases to the presence of positive recruitment, these 13 persons fit in the clinical concept of an incipient disease. Beside these subclinical aberrations, the audiometric examination revealed a moderate to severe sensorineural hypacusis in 17 persons with already developed hearing impairment. Careful examinations with suprathreshold tests may enable us to detect carriers of the gene for autosomal dominant progressive sensorineural hypacusis; this circumstance can be utilized for establishing prognoses with respect to hearing function in the affected families.