Virus fixes DNA mutations for possible hearing loss therapy

Researchers at the Medical School at Harvard and MedUni Vienna’s Department of Ear, Nose and Throat Diseases have managed to harness a virus to deliver restorative genes to the ear. The virus is a modified, non-pathogenic adeno-associated virus (AAV) that was able to restore function to damaged hair cells in mouse models.

There are more than 300 genetic defects that can cause the hair cells in the inner ear do form or are form improperly, leading to difficulty with hearing or complete hearing loss. In particular, the researchers targeted the most common form of congenital deafness in children, which is due to the genetic mutation of GJB2 and GJB6.

The difficulty with treating this disorder is due to the difficulty in introducing ‘repair genes’ into the hair cells so that they can function correctly. This may no longer be the case, as the use of the virus as a gene vector was able to improve the function both inner and outer hair cells.

MedUni Vienna hinted at the future potential for the treatment: "Once the functionality of the virus had been initially proven in the treatment of a mouse model for Usher syndrome, which is the commonest cause of deafblindness worldwide, further studies are required to determine the tolerability of the vector, so that this approach will soon be available for treating newborn babies with congenital hearing loss."

The study holds plenty of promise but treatment in humans is still far away from. There are predictions that it may be possible in three years but potentially even longer. However, the research points the way towards a promising a new frontier for treatment. The particular virus in this case, AAV, has already been used for restoring liver cells and cells in the retina.