There’s outstanding news for sufferers of Duchenne muscular dystrophy: scientists have discovered that gene editing has been very successful in a recent test on mice.

Researchers at Duke University used the CRISPR-Cas9 gene editing system to delete the DNA that was keeping cells from proding a vital protein to muscle function, according to a BBC report.

The findings, published in the journal Science, found that the gene editing test actually improved muscle strength in the mice by using a virus to deliver those alterations directly into the bloodstream. It’s a huge development that could change how Duchenne muscular dystrophy sufferers are treated in the future.

Said Chris Nelson, the lead on the study, according to the BBC: “”We know what genes need to be fixed for certain diseases, but getting the gene editing tools where they need to go is a huge challenge. The best way we have to do it right now is to take advantage of viruses, because they have spent billions of years evolving to figure out how to get their own viral genes into cells.”

The CRISPR-Cas9 gene editing system is a surprisingly simple and inexpensive one, discovered just three years ago and is now being examined all around the world by researchers for its promising abilities. The Crispr system essentially examines the genome and then uses the protein, dubbed Cas9, to slice out the right DNA.

Humans with Duchenne muscular dystrophy, or DMD, experience a loss of muscle function and more weakness. They lack the muscle protein dystrophin, which protects muscles from getting injured.

“Recent discussion about using CRISPR to correct genetic mutations in human embryos has rightfully generated considerable concern regarding the ethical implications of such an approach,” said Dr. Charles Gersbach in a statement, who is associate professor of biomedical engineering at Duke University. “But using CRISPR to correct genetic mutations in the affected tissues of sick patients is not under debate. These studies show a path where that’s possible, but there’s still a considerable amount of work to do.”