Health UK (Commonwealth Union) – An international team of researchers, spearheaded by the University College London (UCL) and the NIHR Great Ormond Street Hospital Biomedical Research Centre, has developed a gene therapy in mice that holds promising potential for significantly mitigating hearing loss linked to Norrie disease.
Norrie disease is a rare yet devastating genetic ailment characterized by both blindness and hearing impairment, predominantly afflicting boys. Affected children are born blind and experience a gradual onset of hearing loss, typically starting around the age of 12.
Presently, the sole available treatment option for managing hearing loss in Norrie disease is cochlear implants, but their effectiveness is limited.
This innovative research has revealed that gene therapy can intervene to prevent the demise of crucial hair cells in the cochlea, responsible for sound perception in the inner ear. Consequently, it has the potential to halt the hearing loss associated with Norrie disease.
Professor Jane Sowden, leading the study at the UCL Great Ormond Street Institute of Child Health and serving as the co-theme lead of tissue engineering and regenerative medicine at the NIHR GOSH BRC, expressed optimism, stating, that she hoped that gene therapy for hearing loss that arises from genetic mutations will soon become available to patients.
“In this study we were able to reduce the progressive hearing loss in a Norrie disease model by gene therapy for the first time. The treatment in mice was successful not only for newborns but also when we treated at a stage comparable to children and young people.
“This is exciting progress as it lays the groundwork for future application in patients – this could be transformative for them and their families and carers.”
In pursuit of this objective, the research team administered a gene therapy specifically crafted to reinstate the absent norrin protein. Their experimentation demonstrated notable improvements in the abnormal blood vessels within the ears and eyes of mice afflicted with Norrie disease.
The researchers are optimistic that this breakthrough could have the potential to forestall deafblindness, as assessments revealed improved hearing and vision in mice following the gene therapy treatment.
Co-author Dr. James Wawrzynski from the UCL Great Ormond Street Institute of Child Health indicated that children suffering from Norrie disease experience a gradual deterioration in their hearing as a result of a defective NDP gene, which plays a crucial role in the structures of the inner ear. The study showcases that, in mice affected by Norrie disease, they can rectify this defective gene by introducing billions of ‘repaired’ copies into the bloodstream. This gene therapy appears to result in enhanced blood vessel structure in the inner ear, and notably, it safeguards the sensory hairs.
Dr. Valda Pauzuolyte, the lead author from the UCL Great Ormond Street Institute of Child Health, indicated that their previous research has illuminated how Norrie disease impacts the sensory hair cells within the inner ear, resulting in hearing loss. Once these cochlear hair cells are lost, they cannot regenerate. This latest study demonstrates the remarkable effectiveness of NDP gene therapy in preventing further harm to the hair cells and preserving hearing in mice with Norrie disease.
Dr. Pauzuolyte continued, emphasizing the significance of this research, indicated that hearing is among the most vital of our senses. While individuals with Norrie disease already experience vision loss from birth, their work offers a glimpse of the potential to help them retain their hearing—a profoundly important sense.
At the time this research received funding, the Norrie Disease Foundation, a patient advocacy group providing crucial support to families affected by the condition, expressed their hope, stating, they aspire to see this research led to a treatment that prevents the blind community from also losing their hearing.
