Everybody knows that injuries, noise exposure and certain illnesses can result in hearing loss, but are your genes involved? Yes. Hearing loss can have a genetic cause. If you look at the numbers, genetic causes are actually the main category of hearing losses. Additionally, hearing loss is regarded as the most prevalent birth defect in the developed world.
DNA, genes and inheritance. Our is DNA composed of genes, which behave like little pieces of code that, when set in a specific combination, cause us to look and function the way we do. Researchers have discovered more than 100 genes that can negatively affect hearing. Hearing loss can result from any one of these genes being missing or altered. Parental genes are passed to children, so any irregular gene sequences which produce hearing loss are passed down.
Categories of genetic hearing loss. Genetic hearing losses can stem from flaws in the outer ear, inner ear or both areas. The hearing loss can be conductive, sensorineural or mixed. Additionally, some genes may cause hearing loss before a child learns to speak (prelingual hearing loss), and other genes cause hearing impairments that show up after speech is learned (postlingual hearing loss). Some of the genetic conditions are common enough to have names. For example, Usher syndrome impacts about half of the deaf-blind population. Waardenburg syndrome is another prevalent disorder that affects hearing in the inner ear but also causes pale skin, a streak of white hair, and light or multi-colored eyes.
Is there any good news? Thankfully, hearing loss isn’t necessarily passed from parent to child. Most genes linked to hearing loss are recessive, which means that even when an individual has an irregular gene, that gene won’t always result in problem so long as a normal copy is received from the other parent. It is not uncommon for the children of hearing impaired parents to have normal hearing. Since there are hundreds of genes involved in hearing, it is much more likely than not that the parental hearing losses do not share the same cause. For people concerned about a family history of hearing loss, genetic testing and counseling is available.