Two children who were born deaf can now listen and dance to music after undergoing ground-breaking gene therapy.
The treatment, given as an infusion into the ear, works by replacing faulty DNA which causes a type of inherited deafness known as DFNB9.
Researchers hope a similar approach could help in other congenital cases of deafness – which account for 60 per cent of the 430 million cases worldwide.
In the world-first gene-therapy trial, five children in China – two girls and three boys, all around three years old – gained hearing in both ears. All five were able to hear and speak words and locate where a sound was coming from.
Dr Yilai Shu from Eye & ENT Hospital of Fudan University examining a young patient
The DFNB9 strain of deafness is caused by a failure to produce a protein known as otoferlin
But two showed more advanced improvements and were even able to respond to music, which has more complex sound signals.
The latest results, reported in Nature Medicine, build on work the team carried out two years ago when they treated children in one ear.
After the gene therapy, the youngsters went from being profoundly deaf to having mild to moderate hearing loss in the treated ear. But administering the therapy in both ears reaped additional benefits compared with the previous trial, the team said, including being able to hear in noisy environments.
The DFNB9 strain of deafness is caused by a failure to produce a protein known as otoferlin, which is necessary for the transmission of the sound signals from the ear to the brain. Currently, a cochlear implant is the only effective treatment for patients.
For the trial, researchers at the Eye & ENT Hospital of Fudan University in Shanghai used a modified version of the adeno-associated virus (AAV), which is not harmful to humans, to deliver the genes.
After the gene therapy, the youngsters went from being profoundly deaf to having mild to moderate hearing loss in the treated ear (stock photo)
The study’s main author, Professor Zheng-Yi Chen, said: ‘The results from these studies are astounding.
‘We continue to see the hearing ability of treated children dramatically progress and the new study shows added benefits of the gene therapy when administrated to both ears, including improvements in speech recognition in noisy environments.’
Professor Chen, who is also an associate professor of otolaryngology – head and neck surgery – at Harvard Medical School in the US, added: ‘Our ultimate goal is to help people regain hearing no matter how their hearing loss was caused.’
It comes six months after a girl in the UK received a similar type of gene therapy in a trial at Addenbrooke’s Hospital in Cambridge. Opal Sandy, 18 months, from Oxfordshire, had the treatment in her right ear while her left had a cochlear implant.
After a few weeks she was able to hear loud sounds, such as clapping, and can now hear soft sounds, such as a whisper, and is starting to say words such as ‘mama’, ‘dada’ and ‘uh oh’.
‘The results are astounding’
***
Read more at DailyMail.co.uk