An 18-month old British girl who was born completely deaf is believed to be the youngest person to have their hearing restored after undergoing groundbreaking new gene therapy.

Several medical teams around the world including in China and the United States have been trialling similar treatments with good results for hereditary deafness that focuses on a rare genetic mutation.

But UK ear surgeon Manohar Bance said the toddler, Opal, was the first person in the world to receive therapy developed by US biotech firm Regeneron and "the youngest globally that's been done to date as far as we know".

Opal was treated at Addenbrooke's Hospital in Cambridge, part of Cambridge University Hospitals NHS Foundation Trust, in eastern England.

Bance called the results of Opal's surgery "spectacular – so close to normal hearing restoration. So we do hope it could be a potential cure".

He said it came on the back of decades of work and marked "a new era in the treatment of deafness".

The little girl, from Oxfordshire in south central England, has a genetic form of auditory neuropathy, which is caused by the disruption of nerve impulses travelling from the inner ear to the brain.

Auditory neuropathy can be caused by a fault in the OTOF gene, which is responsible for making a protein called otoferlin. This enables cells in the ear to communicate with the hearing nerve.

To overcome the fault, the "new era" gene therapy from Regeneron delivers a working copy of the gene to the ear.

Bance said that following surgery last September, Opal's hearing was now "close to normal" with further improvement expected.

A second child received the gene therapy in Cambridge with positive results seen six weeks after the surgery.


China has been working on targeting the same gene though Bance said theirs used a different technology and slightly different mode of delivery.

Medics in Philadelphia have also reported a good outcome with a type of gene therapy on an 11-year-old boy.

Opal was the first person to take part in a gene therapy trial being carried out in Cambridge by Bance.

The trial consists of three parts, with three deaf children, including Opal, receiving a low dose of gene therapy in one ear only.

A different set of three children will get a high dose on one side. Then, if that is shown to be safe, more children will receive a dose in both ears at the same time.

Up to 18 youngsters from the UK, Spain and the United States are being recruited to the trial and will be followed up for five years.

Bance said the current treatment for auditory neuropathy was implants.

"My entire life, gene therapy has been 'five years away'… to finally see something that actually worked in humans… It was quite spectacular and a bit awe-inspiring really," he said.

© Agence France-Presse