A deaf toddler can hear thanks to a world-first gene treatment that took just 16 minutes

After receiving treatment to correct a faulty gene, 18-month-old Opal Sandy can now hear.

• Opal Sandy, a British toddler, was born deaf due to a faulty gene.
• In a groundbreaking gene therapy trial, she has now regained her hearing.
• The trial involved injecting a harmless virus containing the correct gene into her ear.

A deaf toddler has had her hearing restored after being the first patient treated in a gene therapy trial.

Opal Sandy, who is 18 months old, has auditory neuropathy, a condition caused by a faulty gene.

The condition means the ear can detect sound but doesn't transmit it to the brain properly. It can cause degrees of hearing loss, but in Opal's case, she was fully deaf from birth.

Now Opal, who lives in Oxfordshire in England, can hear almost normally thanks to a 16-minute long gene therapy procedure.

Doctors injected Opal's right ear with a harmless virus that carried a working version of the faulty gene while she was under general anesthesia.

Within four weeks of receiving the gene therapy, Opal could respond to sound. After 24 weeks, she had hearing levels that were "close to normal," according to a press release from Britain's health service.

She can hear whispering in her treated ear, respond to her parents' voices, and has even begun saying words such as "daddy" and "bye-bye" herself.

Around 1 in 500 babies are born with hearing loss or develop it in early childhood, according to the Centers for Disease Control and Prevention in the US. 50 to 60% of this hearing loss is due to genetic causes.

The World Health Organization estimates that unaddressed hearing loss represents a global cost of $980 billion a year in costs such as healthcare and educational support.

The "start of a new era"

Auditory neuropathy is caused by a faulty gene and isn't usually detected until a child is 2 to 3 years old, when delays in speech are more noticeable. But Opal's was picked up early through gene testing, which she was eligible for because her older sister has the condition.

Usually, auditory neuropathy is treated with implants, but Opal was put on a trial at Addenbrooke's Hospital in Cambridge, England, which is trialing gene therapy on children.

Her treatment was part of phase one of the trial, where children are given a low dose in one ear. Phase two will involve a higher dose, still in one ear, and phase three will move on to treating both ears at a dose deemed safe from the previous phases.

Opal was the first patient, treated in September 2023 when she was 11 months old. A second child received the therapy and has seen good results six weeks post-treatment, according to a release from Regeneron, the pharmaceutical company that makes the infusion.

Professor Manohar Bance, an ear surgeon and chief investigator of the trial, said the results were "spectacular and better than I expected."

"This is hopefully the start of a new era for gene therapies for the inner ear and many types of hearing loss," Bance said.