A team of researchers from the Cedars-Sinai Medical Center in California has for the first time tested a gene-editing tool on mice with a hereditary degenerative disorder of the retina that routinely leads to blindness. The results of the animal study were positive, paving the way for potential use in humans.

The study focused on a condition called retinitis pigmentosa, which eventually causes blindness in patients. While relatively rare, it's the most prevalent inherited disease of the retina, affecting around one in 4,000 people in the US and Europe.

In an attempt to tackle it, the Cedars-Sinai team turned to a breakthrough gene-editing tool called CRISPR, which was adapted from a system used by bacteria to nullify attacking viruses. The tool allows researchers to program the protein Cas9 to switch off genes as desired, in this case targeting a mutated gene that causes the loss of photoreceptors in the eye.

The method was tested on laboratory mice engineered to have the disease, with their ability to see measured via a test that required the rodents to turn their head in response to visual stimuli. The results were promising, with just one injection causing a noticeable improvement in the sight of the rats when compared to a control group.

"This is the first time CRISPR/Cas9 gene editing has been used to prevent vision loss in a living animal," said study co-author Clive Svendsen. "It is a truly remarkable result and paves the way for more exciting studies and translation to the clinic in the future."

The results of the work were published in the journal Molecular Therapy.