[Audiologic analysis of a family with nonsyndromic genetic progressive sensorineural hearing loss]

To analyze the audiological data collected from a large six-generation family with nonsyndromic genetic progressive sensorineural hearing loss.

There were 104 members in the family who could provide the hearing data, in which 46 individuals had hearing impairment. The pure tone threshold in 56 individuals and ABR in 49 individuals were analyzed. The pedigree of 104 family members with 6 branches was made.

Hearing impairment was found in the second decade. The hearing thresholds of high and mid frequencies were deteriorated up to 110 dB HL in the fourth decade. The hearing loss started from high frequencies and quickly expended to mid and low frequencies. The regression analysis of pure tone thresholds of 4 kHz and 8 kHz in 6 cases with ages from 10 to 20 years were carried out. The regression coefficients, or the annual threshold increases were 15.96 dB and 15.34 dB per year, respectively. ABR results showed that the hearing loss was caused by cochlear impairment. The pedigree of family indicated high or complete penetrance.

The medical history and audiological analysis of the family members showed that this hearing impairment was nonsyndromic autosomal dominant progressive sensorineural hearing loss. The hearing impairment and onset age in this family were different from those families with 13 loci related autosomal dominant nonsyndromic sensorineural hearing loss reported previously. The genetic linkage study showed that it could not link to these regions and other two regions reported recently in Internet.