Baby ear

A new ‘genetic patch’ in early animal testing has shown promising results for preventing a hereditary form of deafness, say scientists at the Rosalind Franklin University of Medicine and Science, Chicago, US.

In an early animal clinical trial, the results of which are published in Nature Medicine journal, the scientists were able to correct some hearing defects in mice using the genetic strip.

A hearing defect that runs in the family is known as Usher syndrome, caused by defective sections of a person’s genetic code, which can cause problems with hearing, sight and balance.

During the trials, mice with Usher syndrome were injected with the ‘genetic patch and grew up able to hear with no balance problems.

For the first couple of months their hearing was close to normal in the lower frequencies, but had started to deteriorate by six months.

There are different types of Usher syndrome related to different errors in a patient’s DNA. One particular form, descended from French settlers in North America, stops people building a protein called hormonin, which is needed to form tiny hairs in the ear that detect sound. This can result in hearing loss at birth and also, due to other factors, loss of eye sight.

Head of biomedical research at Action on Hearing Loss, Dr Ralph Holme, said, "It is encouraging that researchers have been able to rescue hearing using an approach which targeted a specific type of inherited deafness.

"More research is now needed to understand how this new therapy could be used to treat this particular type of Usher Syndrome in humans and discover whether vision can also be rescued."

Researchers do not know why, but treatment had to be given early, within the first 10-13 days of life. This is something that could prove difficult in humans as they spend a lot longer in the womb than mice.

Researcher Michelle Hastings, assistant professor at Rosalind Franklin University, told the BBC, "It was a surprising result that we could treat mice right after they are born and have such a profound effect."

Image: Scients were able to stop genetic hearing loss in mice by injecting a ‘genetic patch.’ Credit: Jeff Terry