Scientists have developed a CRISPR gene-editing technique that can potentially correct a majority of the 3,000 mutations that cause Duchenne muscular dystrophy (DMD), a genetic disorder characterised by progressive muscular weakness.

The method, detailed in the journal Science Advances, works by making a single cut at strategic points along the patient's DNA. The method, successfully tested in heart muscle cells from patients, offers an efficient alternative to the daunting task of developing an individualised molecular treatment for each gene mutation that causes DMD. It also opens up possible new treatment approaches for other diseases that have thus far required more intrusive methods to correct single-gene mutations.

"This is a significant step; we're hopeful this technique will eventually alleviate pain and suffering, perhaps even save the lives, of DMD patients who have a wide range of mutations and, unfortunately, have had no other treatment options to eliminate the underlying cause of the disease," said Eric Olson of University of Texas Southwestern Medical Center in the US.

The new strategy can enhance the accuracy for surgical-like editing of the human genome, correcting mistakes in the DNA sequence that cause devastating diseases like DMD. DMD is a rare disease affecting primarily boys and is caused by defects in the gene that makes the dystrophin protein. Normally, the dystrophin protein helps strengthen muscle fibers.

The new study demonstrated how a wide range of mutations can be corrected in human cells by eliminating abnormal splice sites in the genomic DNA. These splice sites instruct the genetic machinery to build abnormal dystrophin molecules, but once the gene is successfully edited it expresses a much-improved dystrophin protein product, enhancing the function of the muscle tissue.

"In fact, we found that correcting less than half of the cardiomyocytes (heart muscle cells) was enough to rescue cardiac function to near-normal levels in human-engineered heart tissue," said Chengzu Long, lead author of the study and Assistant Professor of Medicine at New York University Langone Health.