‘Groundbreaking’ gene therapy cured a baby of her deafness

An 18-month-old girl can hear for the first time thanks to a groundbreaking gene therapy for deafness.

Opal underwent a gene therapy infusion in her right ear during surgery in September after her parents heard about CHORD gene therapy from an ear, nose throat (ENT) surgeon at their local hospital.

The toddler, from Oxfordshire, was also fitted with a cochlear implant in her left ear to ensure she had hearing, after her parents were told she was deaf at four days old.

Opal’s parents, Jo and James Sandy, both 33, said they were ‘gobsmacked’ when they realised she could hear just weeks after the surgery. 

‘It was about three weeks post-surgery, which was about a week after her implant had been turned on,’ Jo said.

‘We were sort of in the routine of testing quite loud sounds like banging, clapping, wooden spoons on saucepans, that kind of intermittent loud noise.

‘I was testing that with her implant on and hadn’t realised that her implant had actually come off, and she turned to pretty loud clapping. I couldn’t believe it.

‘I thought it was a fluke or like a change in light or something that had caught her eye, but I repeated it a few times.

‘I picked my phone up and texted James, and said ‘I think it’s working’. I was absolutely gobsmacked.’

She added that there was ‘no way in a million years’ that she thought Opal would be able to turn to sound without wearing an implant.

The surgeon at the Sandys local hospital knew of Professor Manohar Bance’s work and that he was running a trial using a gene therapy from biotech firm Regeneron at Addenbrooke’s Hospital in Cambridge.

The couple was told they would notice a change in Opal’s hearing within the first six months, which is why Jo was so surprised it happened so soon. 

The Sandys have an older daughter, Nora, 5, who has the same genetic form of auditory neuropathy as Opal and wears cochlear implants, which is the current standard treatment.

The couple said they found out Nora was deaf at nine months old, and was told that any subsequent children could have additional hearing tests at birth.

‘Hearing that Opal was deaf – of course there was a grieving process that we went through the same as when we found out that Nora was as well – but Nora had set the bar really high and we knew what was possible with lots of hard work and support from lots of people,’ Jo said.

James said he noticed a ‘massive’ improvement in his little girl’s hearing in the 18 to 24 weeks post-surgery.

Now, even without the implant in her left ear, Opal can hear perfectly well thanks to the gene therapy. The team at Cambridge University Hospitals said she had near-normal hearing by 24 weeks post-surgery.

CHORD gene therapy uses a modified virus to deliver a working gene to a specific part of the body, such as the ear.

The genome of the virus is replaced with a working version of the mutated gene, and only a few essential parts of the original virus – which are not harmful – remain. 

The CHORD Clinical Trial by the Cambridge University Hospitals NHS Foundation Trust (CUHFT) looks at the use of gene therapy called DB-OTO for children with Otoferlin gene (OTOF) mutations – a gene that can cause profound hearing loss. 

The therapy entails a DB-OTO injection inside of the ear during a surgical procedure that takes place under general anaesthesia, which is similar to the surgery for a cochlear implant. 

The DB-OTO contains a modified small virus, known as the adeno-associated virus (AAV1) that can deliver genetic material to specific cells and release it to restore function.