CRISPR treats genetic disorder in adult mammal

Researchers have used CRISPR to treat an adult mouse model of Duchenne muscular dystrophy. This marks the first time that CRISPR has successfully treated a genetic disease inside a fully developed living mammal with a strategy that has the potential to be translated to human therapy.

Researchers from Duke University had previously used CRISPR to correct genetic mutations in cultured cells from Duchenne patients, and other labs had corrected genes in single-cell embryos in a laboratory environment. But the latter approach is currently unethical to attempt in humans, and the former faces many obstacles in delivering treated cells back to muscle tissues.

Another approach, which involves taking CRISPR directly to the affected tissues through gene therapy techniques, also faces challenges, particularly with delivery. In the new study, Duke University researchers overcame several of these obstacles by using a non-pathogenic carrier called adeno-associated virus, or AAV, to deliver the gene-editing system.

"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 Gersbach, 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."

Duchenne muscular dystrophy is caused by problems with the body's ability to produce dystrophin, a long protein chain that binds the interior of a muscle fiber to its surrounding support structure. Dystrophin is coded by a gene containing 79 protein-coding regions, called exons. If any one exon gets a debilitating mutation, the chain does not get built.