Deafness Treatment: Breakthrough Gene Therapy Restores Hearing in 5 Out of 6 Children

A breakthrough gene therapy was able to restore hearing to five of six deaf children aged one through 11 years in a world first.

The children involved in the treatment were part of two experimental groups in China and the United States. They were all born with a gene mutation that blocked the production of a protein that is needed for hearing.

Breakthrough Gene Therapy

During the experiments, scientists injected a version of the gene, called otoferlin (OTOF), into the children's inner ear and the cells began producing the missing protein. The subjects' hearing levels were then raised to 70% normal after 26 weeks of the treatment. Researchers started recording progress at just six weeks after starting the injections.

Progress videos showed a one-year-old responding to his name when called for the first time while another little girl was seen repeating father, mother, grandmother, sister, and "I love you" when she previously was not able to speak.

This week, 11-year-old Aissam Dam was able to hear for the first time after receiving treatment for breakthrough gene therapy at the Children's Hospital of Philadelphia (CHOP). Her case marked the first in the United States, as per the Daily Mail.

A professor at Harvard Medical School, Zheng-Yi Chen, who is also the study author for China's experiments, said that if children are unable to hear, their brains can develop abnormally without intervention.

He added that the results from the latest study were truly "remarkable," adding that they saw the hearing ability of children improve drastically week by week. They were also able to regain some of their speech.

The experiments come as hereditary deafness is the latest condition that scientists are targeting with the use of gene therapy. This is already approved to treat other illnesses, such as sickle cell disease and severe hemophilia.

Restoring Children's Hearing

A hearing loss expert at Columbia University, Lawrence Lustig, said that the findings of the experiments were amazing. He noted that there has never been a therapy that restored even partial hearing for someone who was considered completely deaf other than a cochlear implant, according to Wired.

Over half of hearing loss cases in children are caused by genetic issues and OTOF mutations account for roughly 1% to 8% of those cases. This means that the mutations affect about 200,000 people around the world.

The majority of side effects that were recorded were minor and none of them had any long-term impact on the children. The researchers are still unsure why the sixth child did not respond to the gene therapy. They assume one reason to be that some of the solutions leaked from the inner ear during or after surgery.

The breakthrough gene therapy is spearheaded by Refreshgene Therapeutics, which is also working with OBiO Technology Shanghai on gene therapy for the eye disease known as neovascular age-related macular degeneration.

The development comes as Regeneron Pharmaceuticals in October last year announced positive safety and efficacy results in the first child with profound OTOF-related hearing loss to receive its otoferlin gene therapy, according to Reuters.