Audiometric tests in gene carriers of Norrie's disease.

The purpose of the present study was to validate the reliability of audiometric testing procedures in the identification of carriers of Norrie's disease by using DNA analysis. Potential female carriers of Norrie's disease were investigated by means of Békésy tracing audiometry and stapedial reflex thresholds previously found to reveal carriers of recessively inherited hearing impairment by means of peculiar 'dips' and elevation in the thresholds. Relating the audiometric test results to the outcome of the DNA analysis the previous findings could not be confirmed. In addition no concordance between the two audiometric test procedures was demonstrated, and Békésy threshold tracing exhibited poor repeatability and sensitivity. It is concluded that none of these audiometric test procedures are feasible for detection of carriers of an X-linked hearing disorder, such as Norrie's disease.