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Gene therapy brings hearing to baby girl born deaf

By Ernie Mundell, HealthDay News
A breakthrough gene therapy trial conducted by a team at Cambridge University Hospitals in England brought a world of sound to Opal Sandy, who was born deaf. Photo courtesy of Cambridge University Hospitals
A breakthrough gene therapy trial conducted by a team at Cambridge University Hospitals in England brought a world of sound to Opal Sandy, who was born deaf. Photo courtesy of Cambridge University Hospitals

Opal Sandy was born into a world she could not hear.

The British baby girl, now 18 months old, had a rare genetic condition called auditory neuropathy that interrupted nerve impulses that travel from the inner ear to the brain. She'd been fitted with a cochlear implant, but it could only help so much.

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Then came a breakthrough gene therapy trial conducted by a team at Cambridge University Hospitals in England that's brought a world of sound to little Opal.

"When Opal could first hear us clapping unaided it was mind-blowing -- we were so happy when the clinical team confirmed at 24 weeks that her hearing was also picking up softer sounds and speech," her mother Jo Sandy said in a hospital news release. "The phrase 'near normal' hearing was used and everyone was so excited such amazing results had been achieved."

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Opal is the first child in the U.K. and the youngest in the world to receive the new therapy.

"These results are spectacular and better than I expected," said Dr. Manohar Bance, an ear surgeon at the hospital and chief investigator of the new trial. "Gene therapy has been the future in otology and audiology for many years and I'm so excited that it is now finally here. This is hopefully the start of a new era for gene therapies for the inner ear and many types of hearing loss."

He and his colleagues presented their findings Wednesday at the annual meeting of the American Society of Gene and Cell Therapy in Baltimore.

As the researchers explained, auditory neuropathy can arise from a single variation in a gene called OTOF, responsible for producing a protein called otoferlin. The tiny hairs of the inner ear need otoferlin to transmit signals to nerves responsible for hearing.

The gene deficiency behind auditory neuropathy often goes undetected in newborn screenings, so children with the condition are often not diagnosed until age 2 or 3, when delays in speech have set in.

"We have a short time frame to intervene because of the rapid pace of brain development at this age," Bance said in the news release. "Delays in the diagnosis can also cause confusion for families as the many reasons for delayed speech and late intervention can impact a children's development."

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Opal's parents knew their daughter was at risk for auditory neuropathy because her older sister already had the condition. Gene tests conducted when Opal was just three weeks old confirmed that she too carried the gene variant.

The gene therapy Opal received involved the transmission into her right ear of a working copy of the OTOF gene, delivered during surgery into the ear's cochlea via a harmless virus called AAV1. The baby girl was also fitted out with a cochlear implant in her left ear.

Six months later, the results were already remarkable, her parents and doctors said. Opal could respond to sound even when her left ear cochlear implant was switched off. She could even detect low sounds such as whispers in her treated right ear.

At 18 months, Opal easily responds to her parents' voices and uses words like "Dada" and "bye bye."

"It was our ultimate goal for Opal to hear all the speech sounds," said her father, James Sandy. "It's already making a difference to our day-to-day lives, like at bath-time or swimming, when Opal can't wear her cochlear implant. We feel so proud to have contributed to such pivotal findings, which will hopefully help other children like Opal and their families in the future."

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The global trial is ongoing, and experts believe gene therapy could revolutionize the treatment of hearing loss.

"Many families will welcome these developments, and we look forward to learning about the long-term outcomes for the children treated," Martin McLean, senior policy advisor at the National Deaf Children's Society in Britain, said in the hospital news release. "This trial will teach us more about the effectiveness of gene therapy in those cases where deafness has a specific genetic cause."

More information

Find out more about auditory neuropathy at Cincinnati Children's Hospital Medical Center.

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