Hearing

Ben Squires

Gene therapy breakthrough for treatment of hearing loss

Gene therapy breakthrough for treatment of hearing loss

Audiologist Joan McKechnie from HearingDirect explains the latest gene therapy breakthroughs that could change the way hearing loss is treated in the future. 

Hearing loss is particularly prevalent in older people and by the age of 70, three in four will have some sort of hearing loss. Thankfully, there are some medical breakthroughs occurring in the field of gene therapy that may lead to a new treatment for hearing loss. 

What is gene therapy?

Genes are like an instruction manual for the human body.  They determine what an organism looks like, how it survives and how it behaves in its environment.  Human genes reside in long strands of DNA called chromosomes, of which we have 23. Each gene carries instructions for a particular part of the body to look and behave a certain way. For example, a gene might tell your eyes to be blue. 

Gene therapy inserts new genes into a patient’s cells, usually to replace an abnormal gene and treat an illness.  Scientists can also alter how a gene works within the human body to change its behaviour.

How gene therapy helps with hearing loss

The Stanford Initiative to Cure Hearing loss suggests that 70 per cent of the common forms of sensorineural hearing loss are caused by mutations in three genes.  However, researchers at Harvard University believe that as many as 70 genes can cause deafness when mutated.  If scientists could replace or modify those genes, many forms of hearing loss would become treatable. 

Scientists have already made some positive steps in treating hearing loss that has been caused by a genetic mutation.  Researchers from the Harvard Medical School and Boston Children’s Hospital managed to partially restore the hearing of mice by removing a mutated gene called transmembrane channel–like 1 (TMC1).  The Harvard researchers estimate that the TMC1 gene mutation causes between 4 to 8 per cent of all cases of deafness in humans.  If the gene mutation can be removed from human patients it could help restore the hearing of millions of people.

Researchers have also discovered a gene that plays a role in the regrowth of the hair-like nerve-endings within the cochlea.  If researchers can re-activate the Atoh1 gene, they may be able to treat the hearing loss of millions of people who have sensorineural hearing loss.

A drug that may be capable of doing just that is already in clinical trials.  Biotechnology company Genvec has partnered with Novartis to test the drug, named CGF-166.  The trial began in October of 2014 and is expected to finish in 2017.  If the trial has positive results, there may be a mainstream treatment for many forms of hearing loss within the decade.”

Written by Audiologist Joan McKechnie from UK-based HearingDirect.com.

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