A gene therapy trial in the UK – what does this mean?

Recently, a biotech company, Decibel Therapeutics, announced they had been granted approval  to start a gene therapy trial in the UK to treat people with a particular type of deafness. This would be be the first time gene therapy has been provided to deaf people in Britain. This blog provides info on what this trial means for deaf children and young people.

What is gene therapy?

This is when genes that cause a condition are inactivated or replaced by ‘normal’ genes. One way this can be done is by injecting a virus into a patient’s body and the virus will act as a carrier of the new gene and insert it into a patient’s DNA (their genetic code). This is the process being used in the Decibel Therapeutics trial.

For more information about gene therapy visit: https://www.yourgenome.org/facts/what-is-gene-therapy/

Could this new treatment be used with deaf children?

This trial will test out gene therapy for people who have a particular type of genetic deafness caused by lack of a protein called otoferlin, leading to severe or profound deafness from birth. Otoferlin encodes sounds within the inner ear and allows nerve signals to be sent from the cochlear to the brain. The gene therapy developed by Decibel would insert ‘normal’ genes into the cochlear hair cells so that otoferlin is produced and enable signalling between the ear and the brain.

The gene therapy will only be effective for people who have this particular type of deafness. If you are deaf because of a different gene, then you would not be eligible to take part in the trial.

It is expected that the trial will include patients of a range of ages including children aged 2 and below.

If the trial was effective, would it mean a child would no longer be deaf?

No, this is not likely, but the severity of deafness could be much reduced. The company behind the trial describes itself as trying to provide ‘durable hearing’. Gene therapy trials with deaf mice have not completely restored hearing and we’d expect to see similar results with humans.

Additionally, where gene therapy is carried out on older young people, research suggests it might not compensate for permanent changes in how the brain is wired. Where people have grown up deaf, auditory signals may be processed differently between the ear and the brain than they are in hearing people. It is believed that these cannot be reversed. This means that gene therapy might mean that a deaf person can hear more, but it would be more challenging to process new sounds effectively and understand what these sounds mean.

Are there any risks to gene therapy?

As with many medical treatments, it is not risk-free. There have been cases of adverse immune reactions to gene therapy which can create dangerous side effects including death in rare cases. However, much work has been done in the past couple of decades to find safer ways of carrying out gene therapy. The number of trials being granted permission in recent years by regulators suggests that the most serious safety concerns have now been addressed.

Is this trial controversial?

It may be. Some deaf people do not believe that deafness is something that needs to be cured or eradicated. Many deaf people live happy and fulfilled lives and see being deaf as a positive part of their identity. Others believe that deaf children face too many barriers in life and the best way to overcome these barriers is to find medical treatments for their deafness.

Our view is that families and young people should be free to make the decisions that they believe are best for them. We, however, believe that these should be fully informed decisions. Parents or young people should be made aware of any risks of complications, the limitations of the treatment and understand being deaf is not a barrier in itself to a happy and fulfilled life.

This blog has been written by Martin McLean, our Senior Policy Advisor. Martin has a degree in Genetics and has previously run information projects on genetics for deaf people and their families.