A Q&A with J. Thomas Roland Jr., MD
A novel gene therapy treatment for deafness was reported on in numerous news outlets last week, including Time Magazine and The New York Times. The deafness treated is caused by a mutation in the OTOF gene which encodes the otoferlin protein, produced by cells in the cochlea.
This mutation and cause of deafness is relatively rare; however, researchers believe that the positive results found can potentially lead to developing gene therapy treatments for different, more common kinds of genetic deafness.
CHC’s Medical Director, J. Thomas Roland Jr., Professor Otolaryngology-Head and Neck Surgery and Professor Neurosurgery at NYU Langone Medical Center, participated in a Q&A on the topic which we hope will improve your understanding of this novel treatment method.
J. Thomas Roland Jr., MD, on Gene Therapy for Hearing Loss
CHC: Tell us about the study.
Dr. Roland: The concept is to infuse the ability of the cochlear cells to manufacture the missing protein into the cochlea on a viral vector, or transmitter. The cells within the cochlea are then presumed to be able to create the missing protein and, hopefully, the cells can function normally to transfer the auditory signal to the central nervous system so the child can hear again.
CHC: Tell us about the specific genetic issue/mutation the gene therapy treats.
Dr. Roland: This study is for children who have a deficiency in the Otoferlin gene and, therefore, cannot make a specific protein that is required for the cochlea to transmit the auditory code to the auditory nerve for normal hearing. The cochlear hair cells are normal, and the nerves are normal. Very few children who have a genetic cause to their hearing loss have this specific genetic mutation.
CHC: What type of hearing loss is associated with this particular gene?
Dr. Roland: Often the child has a variable hearing loss and poor speech understanding, even when hearing aids are used. Essentially, when tested, the speech understanding, or discrimination, is much poorer than would be expected. This is what we call auditory dyssynchrony. Previously, many of these children received cochlear implants with good results. The cochlear implant essentially bypasses the defect. The number of children with this problem is relatively small.
CHC: If you have a child with the Otoferlin mutation, what should you do?
Dr. Roland: The first step is to speak to your child’s otologist, and they may be able to direct you to centers that are conducting this research. You can also contact the companies that are involved in this therapy. China has had success with a number of children and the Akouos company in the US has had some success with its first child who received the gene therapy. There are other companies working on this as well. The first step is confirming through genetic testing that the child has the Otoferlin mutation.
CHC: If you have a child with a different genetic mutation, what does it mean for them? Do you think there will be gene therapy in the future for other mutations?
Dr. Roland: With the current study, the proof of concept of gene therapy to treat a genetic form of deafness has been successful, and it suggests that there might be other gene defects effectively treated in the future. It’s impossible to know when new treatment options will be available. While this line of research is well-funded, many researchers have been working on this for many years. The early success of this specific gene therapy suggests that there is potential to look at other genetic causes of hearing loss and try similar therapies on other mutations in the future.
CHC: What do you recommend as far as genetic testing to parents of a newly diagnosed child?
Dr. Roland: A child should be evaluated by a geneticist with experience evaluating people with hearing loss. The geneticist will determine which of the over 300 genetic defects to test for, based on the type of hearing loss presented, the family history, and the presence or absence of other physical symptoms and characteristics.
We hope this addressed your questions about the recent news on gene therapy treatment for hearing loss and invite you to contact us should you have any further questions. We're here to help.