Six months after groundbreaking gene-therapy treatment, a British toddler who was born deaf can now hear unaided, and has started talking.
Opal Sandy, as part of a trail recruiting patients in the UK, US and Spain, was treated shortly before her first birthday, and can now hear sounds as soft as a whisper and is beginning to talk, saying “Mama” and “Dada”, reports the BBC.
Given as an infusion into the ear, the therapy replaces faulty DNA that causes her type of inherited deafness.
Doctors in other countries, including China, are now also exploring very similar treatments for the Otof gene mutation Opal has. Hearing loss caused by a variation in the gene is not commonly detected until children are two or three-years-old, when a delay in speech is likely.
Opal’s parents said the results have been “mindblowing”, but allowing their daughter to be the first to test this treatment, made by Regeneron, was extremely tough.
Her sister, Nora, five, has the same type of deafness and manages well wearing an electrical cochlear implant. Rather than making sound louder, like a hearing aid, this gives the “sensation” of hearing by directly stimulating the auditory nerve that communicates with the brain, bypassing the damaged sound-sensing hair cells in the cochlea.
In contrast, Opal’s therapy uses a modified, harmless virus to deliver a working copy of the Otof gene into these cells.
Opal had the therapy in her right ear, under general anaesthetic, and a cochlear implant put into her left.
Just a few weeks later, she could hear loud sounds, such as clapping, in her right ear. And after six months, her doctors, at Addenbrooke’s Hospital, in Cambridge, confirmed that the ear had almost normal hearing for soft sounds – even very quiet whispers.
“It's wonderful seeing her respond to sound,” said chief investigator and ear surgeon Professor Manohar Bance.
More than half of hearing-loss cases in children have a genetic cause.
Bance hopes the trial can lead to gene therapy being used for more common types of hearing loss.
“What I am hoping is that we can start to use gene therapy in young children… where we actually restore the hearing and they don’t need to have cochlear implants and other technologies that have to be replaced,” he said.
BBC News article – Pioneering gene therapy restores UK girl’s hearing (Open access)
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Gene therapy restores hearing in children with hereditary deafness
Best practices for hearing preservation in cochlear implantation
Quicker test being trialled to help prevent permanent deafness in babies