Duchenne explained Glossary of research terms Gene editing (CRISPR/CAS9) CRISPR/Cas9 is a new genome editing technique which is used to make precise changes in the DNA to remove the Duchenne mutation from the genome. Cas9 is an enzyme which can can cut DNA, whilst CRISPR is a short strand of RNA (chemical messenger). There are many different mutations in the dystrophin gene known to cause Duchenne. Scientists have found that most of these mutations are in particular regions of the gene, called hotspots. Scientists have used CRISPR technology to cut out large faulty portions of the gene and have found that removal of these can result in the production of a shorter but functioning version of the protein in mdx mice models of Duchenne. Encouraging studies revealed that targeting exon 23 produced functional recovery in CRISPR/Cas9 treated mice indicated by improved grip strength, reversed cell death and reduced inflammation in muscle. Data suggests this approach could benefit around 60% of people with Duchenne muscular Dystrophy, so the future is optimistic, yet it is still at a very early stage.