A new genetic treatment technique has generated positive results for auditory health: researchers have succeeded in correcting congenital deafness in mice. These results are encouraging for future clinical trials with human subjects.

Publication Optical Center, written by Manu Gosselinois 26.02.2019 - 12h38

What causes deafness in mice?

Congenital deafness is difficult if not impossible to treat. And yet, several researchers from French and US institutions have successfully treated a hearing deficiency in mice. The mice in particular suffered from congenital deafness caused by a missing gene. These researchers were the first in the world to cure such an ailment. The mice presented the DFNB9 genetic mutation, responsible for 2-8% of all gene-related cases of human deafness. Persons suffering from this mutation are profoundly deaf and lack the gene that codes for OTOF (otoferlin), a protein essential to the transmission of auditory signals to the brainstem. It is the leading cause of congenital deafness at birth.

How can hearing problems be corrected?

For now, the only way to correct this anomaly is to use cochlear implants inserted in the ear. In order to treat the mice for their deafness, however, the researchers “replaced” the defective gene responsible for their hearing deficiency with a healthy gene. They then injected the healthy gene, coding for the missing protein, and the mice recovered a virtually normal level of hearing after two weeks. This experiment falls into the category of gene therapy, also known as gene manipulation.

What does the future hold for this type of deafness?

The results of this research are currently the subject of a patent application on local gene delivery to the cochlea. This technique for hearing loss correction, which involves injecting a foetus with the healthy gene, is the only way to correct this congenital hearing anomaly. The next step will be to conduct gene therapy trials on human subjects. Scientists hope that this success can be applied to other forms of deafness linked to other genes. Given that 60-80% of all cases of hearing deficiency are genetic, they are potentially treatable using this technique.