gms | German Medical Science

Introduction: Hearing loss is one of the most frequent expressions of sensorial diseases. The causes of hereditary hearing loss are still mostly unknown. Finding the responsible antecedents can be greatly facilitated by investigating families with a history hearing loss.

Methods: Over the last 2.5 years we studied two families with hereditary hearing loss. To identify correct phenotypes it is vital to take precise case histories and perform appropriate audiometric measures. For DNA assays we extracted blood or used the patients` oral mucosa. Results: In one family 5 out 25 members demonstrated an autosomal recessive, non-syndromic form of hearing impairment. Here we found a co-segregation of hearing loss on chromosome 16. In the other family comprising 3 generations we were able to identify a dominant autosomal inherited sensorineural, progressive non-syndromic form of hearing impairment in 8 out of 21 family members. With advancing age these patients demonstrated the typical progressive hearing loss of 2 kHz. Conclusions: Within the autosomal recessive family we found that hearing loss was linked to the DFNB 22 locus. Currently, we are sequencing genes in this area. However, we were unable to determine a locus for the dominant autosomal family. For this reason we are now conducting a complete genome scan.