Genetic Hearing Loss Explained

Did you know hearing loss can be hereditary? It’s true, many forms of hearing loss are actually genetic. Approximately 1 out of 500 infants are born with or eventually have hearing loss throughout their childhood. Genetic factors can make some people more susceptible to hearing loss than others. Their genes make them more predisposed to hearing loss due to ageing or induced by noise, drugs or infections.

hereditary-deafnessWhat is Hereditary Hearing Loss?

When hearing loss is passed from the parents on to the children, it is called hereditary hearing loss. Hereditary hearing loss can be inherited from either one or both parents who either do or do not have hearing loss. Hereditary material or genes are located on chromosomes which are found in each cell of the body. Genes provide instructions for specific traits or characteristics such as hair color or blood type. Defective genes can also pass along traits such as hearing loss or speech and language disorders which can lead to hereditary deafness.

The hereditary hearing loss that results from defective genes may be syndromic or nonsyndromic, dominant or recessive. Syndromic hearing loss is associated with specific traits additional to hearing impairment. Nonsyndromic hearing impairment has hearing loss as its only characteristic. Dominant transmission of deafness requires only one faulty gene, from either the mother or father to cause the hearing loss, whereas recessive transmission of deafness requires a faulty gene from both the mother and father.

Hereditary hearing loss can be detected through a physical exam, otological, and audiological exams. A CT scan of the temporal bone and molecular genetic testing are also taken. The family history is reviewed as well. All these test assist in figuring out whether the hearing loss is hereditary or non-hereditary.

Researchers and scientists around the world are continuing to explore the genetics of hearing loss in a variety of disorders, including Waardenburg syndrome, Usher syndrome, nonsyndromic hereditary deafness, otosclerosis, adult-onset hearing loss and presbycusis and the hereditary predisposition to noise-induced hearing loss and otitis media. This research should lead to a better understanding of how hearing impairment or deafness is transmitted from parent to child, making it possible to identify and characterize the genes in which changes or mutations cause hearing impairment. Other scientists are experimenting with gene therapies which may become important treatments of hereditary and genetic hearing loss in the future, perhaps in combination with stem cell therapy.

If there is a family history of hearing loss, it is strongly recommended to have the children be genetically tested to find any abnormalities that may lead to hearing loss and have an audiometry screening as soon as possible. Until medical professionals have made a final diagnosis and management plan it is recommended to have your children avoid loud noises for any lengthened period of time.