Researchers Are Working on a Way to Reverse Deafness

Boston Children's and Harvard scientists successfully treated hearing loss in mice.

Researchers from Boston Children’s Hospital and Harvard Medical School (HMS) used gene therapy to reverse genetically inherited deafness in mice, and believe the same technique could someday be used as a treatment for hearing loss in humans.

The researchers studied two groups of mice, one with a condition meant to mimic a type of human hearing loss that usually presents itself by age 2, and another that typically manifests between ages 10 and 15. To treat the deaf mice, the team added healthy genes to their system by injecting them with a specially engineered virus and a promoter, a genetic sequence that turns on the new, functional gene. Administering the new gene reversed hearing loss and improved brainstem activity in the first group of mice, and improved hearing-related cellular and brain function while partially treating deafness in the second group.

While the discovery, published Wednesday in the journal Science Translational Medicine, is promising, researcher Jeffrey Holt, an otolaryngologist at Children’s and HMS, cautioned that clinical trials in humans may not start for another five to 10 years. The viral vector used in the experiment, however, is already used in human gene therapy trials for blindness, heart disease, and muscular dystrophy, so it’s a promising option for deafness treatment as well.

In a statement, Holt says gene therapy could be a key avenue for treating the 70 types of genetic deafness, which affect between one and three people out of every 1,000 born. “I can envision patients with deafness having their genome sequenced and a tailored, precision medicine treatment injected into their ears to restore hearing,” Holt says.