A powerful gene-editing technique can stimulate dogs’ production of an important muscle protein, a finding that takes researchers a step closer to trying the technology in humans who have a fatal deficit in the same molecule.
People with the genetic disease Duchenne muscular dystrophy cannot synthesize dystrophin, a component of the scaffolding inside muscle cells. This deficiency results in muscle wasting and early death. The CRISPR–Cas9 gene-editing system has previously been used to trigger dystrophin production in mice, but Eric Olson at the University of Texas Southwestern Medical Center in Dallas and his colleagues sought to test the technique in a larger animal.
The researchers treated four dogs — all lacking dystrophin because of a genetic mutation — with the CRISPR–Cas9 system, which snipped out a short stretch of the animals’ DNA. This allowed the dogs’ cells to make dystrophin. Levels of the protein in one dog’s heart muscle reached 92% of normal.