A study published in the Journal Science Translation Medicine has discussed the successful restoration of hearing in mice with genetic forms of deafness by using gene therapy. The research offers hope for children born with genes that cause profound hearing loss.
70 DIFFERENT GENES CAN RESULT IN DEAFNESS
This has opened the doors for researchers to try the same on humans. More than 70 different defective genes are known to result in deafness. The scientists in this study focused on one gene called the TCM1. It is responsible for between 4-8 percent of cases of deafness and plays a central role in hearing by coding for important inner ear protein.
HARVARD MEDICAL SCHOOL’S GENE THERAPY PROTOCOL ISN’T READY
Boston Children’s Hospital and Harvard Medical School has said that their gene therapy protocol isn’t prepared for clinical trials. They need to tweak it a little in order to use it but there are sure that this could be used for therapeutic use in humans.
GENE THERAPY TESTED IN TWO TYPES OF MICE
The researchers tested gene therapy in two types of mutant mice. One type of mice had the TMC1 gene completely deleted and is the perfect model for the recessive TCM1 mutations in humans. Children who have two mutant copies of TCM1 have acute hearing loss from a young age, around two years old. This treatment was tested on two strains of mutant mice, representing different forms of TCM1-related deafness in humans. One mouse had no functioning TCM1 gene, and children with this kind of recessive genetic defect go deaf from a very young age.
The other strain, called Beethoven, had a less common form of TCM1 deafness caused by one copy of the paired genes not working. This “dominant” defect causes children to go deaf gradually from between the ages of 10 to 15.
In the recessive deafness, gene therapy with TCM1 restored the ability of sensory hairs to respond to sound producing a measurable electrical current and restored activity to the auditory part of the brainstem. In the dominant deafness model, gene therapy with a related gene, TCM2 was a success at the cellular and brain level and restored hearing partially, as proven in the startle test.
The researchers of this study have envisioned that deaf patients will have their genome sequenced and a precision medicine treatment injected into the ears to restore hearing. This form of therapy and restoration of hearing might be the replacement for the traditional cochlear implant.
Researchers restored the hearing of deaf mice by injecting a virus with the healthy gene into their inner ears. This gene therapy cure was successfully tested and could be offered to human patients in a little under five years.
