TAU Scientists Can Prevent Deafness

Prof. Karen Avraham and Shahar Taiber TAU

Scientists from Tel Aviv University may have developed a new treatment for deafness. The treatment utilizes the delivery of genetic material into the cells of the inner ear. The genetic material “replaces” the genetic defect and enables the cell to continue functioning normally.

The new TAU research only deals with, however, a specific type of deafness. It can be used with children born with various genetic mutations which eventually cause deafness. The scientists were able to prevent the gradual deterioration of hearing in mice with such a genetic mutation for deafness.

The treatment was administered soon after birth and the mice’s hearing was then monitored using both physiological and behavioral tests.

OK, so it worked in mice. But this is the first step in any medical research. The procedure will need to be tested on people eventually.

But before anyone celebrates a cure for deafness it needs to be pointed out that science is years away from developing one. It takes time to get to a human testing stage in research. And performing what is, in effect, a transplant of genetic material may not be well received in dome quarters, especially on children. And even if they move forward with human testing, it will take years to determine if the procedure actually works and to see if there are any adverse side effects.

The study was led by Prof. Karen Avraham and Shahar Taiber, a student in the combined MD-PhD track, from the Department of Human Molecular Genetics and Biochemistry at the Sackler Faculty of Medicine, and the Sagol School of Neuroscience, and Prof. Jeffrey Holt from Boston Children’s Hospital and Harvard Medical School. Additional contributors included Prof. David Sprinzak from the School of Neurobiology, Biochemistry and Biophysics at the George S. Wise Faculty of Life Sciences at Tel Aviv University. The paper was published in EMBO Molecular Medicine.

Deafness is the most common sensory disability worldwide. According to the World Health Organization there are about half a billion people with hearing loss around the world today, and this figure is expected to double in the coming decades. One in every 200 children is born with a hearing impairment, and one in every 1,000 is born deaf. In about half of these cases, deafness is caused by a genetic mutation. There are currently about 100 different genes associated with hereditary deafness.

Prof. Avraham: “In this study we focused on genetic deafness caused by a mutation in the gene SYNE4 – a rare deafness discovered by our lab several years ago in two Israeli families, and since then identified in Turkey and the UK as well. Children inheriting the defective gene from both parents are born with normal hearing, but gradually lose their hearing during childhood.

This happens because the mutation causes mislocalization of cell nuclei in the hair cells inside the cochlea of the inner ear, which serve as soundwave receptors and are thus essential for hearing. This defect leads to the degeneration and eventual death of hair cells.”

Shahar Taiber: “We implemented an innovative gene therapy technology: we created a harmless synthetic virus and used it to deliver genetic material – a normal version of the gene that is defective in both the mouse model and the affected human families. We injected the virus into the inner ear of the mice, so that it entered the hair cells and released its genetic payload. By so, we repaired the defect in the hair cells, and enabled them to mature and function normally.”