Hearing loss (HL) is the most common sensory disorder, affecting all age groups, ethnicities, and genders. According to World Health Organization (WHO) estimates in 2005, 278 million people worldwide have moderate to profound HL in both ears. Results of the 2002 National Health Interview Survey indicate that nearly 31 million of all non-institutionalized adults (aged 18 and over) in the United States have trouble hearing. Epidemiological studies have estimated that approximately 50% of profound HL can be attributed to genetic causes. With over 60 genes implicated in nonsyndromic hearing loss, it is also an extremely heterogeneous trait. Hearing loss can be acquired or inherited and can also be either syndromic or non-syndromic. Recent progress in identifying genes responsible for hearing loss enables otolaryngologists and other clinicians to apply molecular diagnosis by genetic testing. However, the routine application of these tests is hampered by the large number of genes involved in HL and by the fact that molecular screening of these genes is often quite expensive and time consuming. Only a minority of these genes is currently included in genetic diagnostics. In childhood hearing loss, early educational intervention is required in addition to medical intervention for normal development of speech and language. In addition, even severe to profound hearing loss may be restored very effectively by hearing aids or cochlear implants. Because of these features of sensorineural hearing loss (SNHL), genetic testing has exceptionally high value in the medical practice for hereditary hearing loss. Several strategies are used for genetic testing of SNHL for accurate and efficient identification of the genetic causes, and the results were used for explanation of the cause, prediction of auditory features, prevention of deafness, management of associated symptoms, determination of therapy, and genetic counseling. Implementing new and powerful DNA high throughput sequencing technologies is likely to happen within the next several years, and will cause a breakthrough in terms of power and cost efficiency. This ability will greatly improve DNA diagnostics. This chapter focuses on describing clinical implications of the most frequent genes including GJB2, which is responsible for more than half of cases, followed by SLC26A4, MYO15A, OTOF, CDH23, TMC1, WFS1, MYO7A, and COCH and a cost-effective stepwise diagnostic paradigm for sensorineural hearing loss.
|Original language||English (US)|
|Title of host publication||Hearing Loss|
|Subtitle of host publication||Classification, Causes and Treatment|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||12|
|State||Published - Apr 1 2011|
ASJC Scopus subject areas