Gene Therapy for Hearing Loss

For years, when families asked me about gene therapy for hearing loss, I’d tell them, “I’ve heard at every conference for the past decade that ‘It’s coming’ … and we’re still waiting. I don’t think I’ll see it in my lifetime.”

Well, it’s time for me to eat my words, because we are seeing some very early clinical results from gene therapy. What does this mean for children with hearing loss, their families, and the professionals who serve them?

Some things to keep in mind:

• Currently, gene therapy has been successful in patients with an OTOF gene mutation, which disrupts the body’s production of the otoferlin protein. The results have been very promising, with about 80% of patients experiencing improved hearing.
  • If your/your child’s deafness is due to a different cause, then there is still no gene therapy solution for you. Of course, gene therapy to treat other causes of deafness is in the works, but it may be more complicated. People with OTOF-related deafness have the correct structures in their inner ear, just not the correct protein. The treatment helps their bodies produce that protein. Other causes of deafness that are due to structural changes in the inner ear (e.g., the cochlea’s hair cells are absent or damaged) are going to be much harder to treat — for those, we’re not just fixing a single protein (and I say “just,” but that’s still a massive achievement!), we’re having to grow (or re-grow) a damaged structure.
• Hearing loss is still a neurodevelopmental emergency. The clock is ticking on language development. If parents and caregivers want a spoken language outcome, I would strongly advise against are holding out for gene therapy and not pursuing hearing technology and early intervention.
  • If gene therapy ends up coming out later for your child’s type of hearing loss, their results with restored hearing will be much better if their brain has already learned how to listen. Remember, it’s all about the brain!
  • If gene therapy doesn’t end up being successful for your child’s type of hearing loss, or is never developed at all, or is not developed in their lifetime, you’ve still given your child the tools to become a successful communicator and make a good life for themself.
• While many causes of hearing loss are genetic, others are due to structural malformations, illness, or injury. Hearing loss in general is not going away completely any time soon.
• We also don’t know the long-term effectiveness (how long and how well does it last) or effects (are there any long-term negative ramifications?) of this treatment

And then, of course, there are the ethical questions, which I will gladly leave to minds greater than my own: Is it ethical to alter genes to erase disability? Is it ethical not to? Will this create another case of medical “haves” and “have nots” across the world, with disability and the need for rehabilitation largely occurring in developing nations?

These early outcomes are a huge step — one I honestly didn’t know if I’d ever see in my lifetime — but many questions remain. It’s important for clinicians to be well-informed, because families surely will be asking about gene therapy. As always, they deserve our best, most up-to-date information and guidance so they can make the right choices for their children and their family, and that looks different for everyone!