Columbia Gene Therapy Helps Deaf Siblings Hear for First Time

As Raegan Eller approached her first birthday in June 2021, she hadn’t made any attempts to talk—no babbling or saying “mama” or “dada,” her mother, Erin McLaughlin-Eller, recalls. She also didn’t seem to react when her name was called.

Raegan had passed a newborn screening test that measures otoacoustic emissions to determine whether the ear’s cells can detect and amplify sound. The Ellers were increasingly concerned that the test had missed something, but due to a COVID-related backlog, they were unable to schedule additional testing.

In the meantime, the Ellers had their second child, Emrys, at a different hospital. Like his sister, Emrys passed the otoacoustic emissions test. But a second test that measures auditory brainstem response (how the brain responds to sound) revealed that Emrys had auditory neuropathy spectrum disorder, a condition in which the inner earcan detect sound vibrations but can’t transmit signals to the brain. Depending on the cause—structural or genetic—people with the condition may have mild hearing impairment or profound deafness.

A few months later, when Raegan was 3, she had the same test, as well as an MRI to examine her inner ear. Like her younger brother, Raegan was also diagnosed with auditory neuropathy spectrum disorder.

“We finally had a diagnosis, but there was no real explanation for why our children had this condition,” Erin says. “We did not have a history of deafness in our family, and both pregnancies were normal. All we knew was that our children were completely deaf.”

The Ellers sought genetic testing and discovered that both children had a mutation in the OTOF gene, which makes a protein, otoferlin, in the tiny hair cells inside an ear structure called the cochlea. Otoferlin helps to convert sound waves into nerve impulses that relay sound to the brain. Only about 2%- 8% of children born deaf have this mutation, which typically causes profound deafness.

Considering a new gene therapy

The Ellers had considered getting their children treated with cochlear implants, but it was unclear how much this would help—and the invasive surgery it involved carried possible side effects. The kids were already learning American Sign Language and were otherwise healthy and happy.

At the same time, Lawrence Lustig, MD, a hearing loss specialist at Columbia, was starting enrollment in a clinical trial for a gene therapy developed for children with otoferlin deafness. The therapy, developed by Regeneron Pharmaceuticals, delivers a working OTOF gene directly into the inner ear, increasing production of the protein in the cochlea and enabling the hair cells to transmit sound signals to the brain.

Dr. Lustig noticed the Eller siblings were included in a registry of otoferlin deafness cases and reached out to the family’s otolaryngologist.

“We weren’t sure if the therapy would benefit both children equally in terms of language comprehension and speech, since these skills occur early during a child’s development,” Dr. Lustig says. “But based on previous research, we believed that both children would benefit, even if they improved at different rates.”

In January 2025, when the children were ages 2 and 4, the Ellers traveled from their home in central New York to Columbia University Irving Medical Center in New York City, one of only two medical centers in the Northeast where the therapy was being tested. Dr. Lustig delivered the gene therapy with an injection into both children’s inner ears.

Then everyone waited.

Adjusting the dial

About three weeks after the procedure, Erin noticed something was different.

“One day, I was bathing Emrys when he heard his own laugh echo in the bathtub. He was terrified and began to cry, but he has since taken to hearing very well and mimics everything he hears,” Erin says.

It took a little longer for Raegan to notice the effects. “Raegan didn’t like it very much, but now she is getting used to it,” Erin says. “One day, during a dance party, Raegan realized she could hear the music out of my Bluetooth speaker when it was turned up loud, and she thought that was pretty cool, though sometimes, in the car, she prefers it if we turn down the volume on the radio.”

Emrys now has mild to moderate hearing impairment, and though Raegan’s hearing has improved, it’s still considered severe. Both now wear <hearing aids and are beginning to talk.

“In the trial, we saw the biggest improvements in hearing in the first 12 weeks after treatment,” says Dr. Lustig. “But some people continued to improve over the next one to two years. In the future, we hope to better understand who is likely to benefit the most from this gene therapy.”

According to Erin’s husband Josh, the kids began experimenting with sound by screaming at each other all over the house. As they became more accustomed to hearing, they began learning to moderate their volume.

Overall, the Ellers are happy with their decision to try the gene therapy. Emrys is beginning to explore music and sports, while Raegan is more of a visual artist.

“We debated the pros and cons—and even considered no treatment at all—before ultimately deciding that the safety benefits of being able to hear were too important to ignore,” Erin says. “Even if they still have hearing impairment, we feel more confident that having some hearing ability will allow them to be more independent as they grow.”

Lawrence Lustig, MD, one of the nation's leading experts in hearing loss, is chair of the Department of Otolaryngology—Head and Neck Surgeryat the Columbia University Vagelos College of Physicians and Surgeons and otolaryngologist-in-chief at NewYork-Presbyterian Hospital/Columbia University Irving Medical Center.