| As the result of the Human Genome Project, a considerable amount of new information on genetic hearing impairment is currently available. Geneticists have been able to identify new genes and loci responsible for 70% of non-syndromic hearing impairment. To date, over 80 loci have been reported for non-syndromic deafness: 41 autosomal dominant, 30 autosomal recessive, 8 X-linked, and 5 mitochondrial mutations. In addition, 29 auditory genes have been identified: 15 autosomal-dominant, 12 autosomal recessive, and 2 X-linked. As genes for deafness continue to be identified, genetic testing and genetic counseling become more useful. Clinicians may increasingly refer individuals for genetic services to identify those at high risk of hearing impairment or to identify the cause of hearing loss. Despite the relevance of genetics to hearing healthcare professionals, limited coverage of this topic is disclosed in audiology journals and textbooks. Hearing healthcare professionals should have the knowledge to identify hearing loss that may be the result of hereditary factors and should recognize when genetic services are needed. This project reviewed advances in the identification of genes involved in non-syndromic hearing impairment as well as inheritance patterns (autosomal-dominant, autosomal-recessive, X-linked, and mitochondrial) and their associated phenotypes. A list of the latest genes discovered is provided. Ethical, legal and social implications of genetic testing are reviewed along with the cost involved in genetic services. Finally, a list of resources, including organizations and websites are provided to update professionals on the latest breakthroughs in genetic hearing impairment. This information will inform audiologists regarding the identification of individuals with genetic hearing loss or families at risk of hereditary hearing impairment. |
