Scientists have for the first time used gene-editing to treat Duchenne muscular dystrophy in a large mammal, BBC reports.
In a study on dogs, scientists have been able to partially restore the key protein people with DMD can not make. Children born with the degenerative disease have a genetic mutation that stops them producing dystrophin, and a protein that is vital for muscle strength and function. The same disorder also occurs in many dog breeds.
The study was a collaboration between the Royal Veterinary College in London and the UT Southwestern Medical Center in the US.
Results were published in Science journal.
The condition has no cure. It leads to loss of muscle function and ultimately an early death.
The technique used in the study was for a genetic fault that affects about 13% of people with DMD.But experts say it could potentially be applied to many other mutations those with the condition have.
The research team hopes to test the technique in people.
Using the Crisp gene-editing tool, scientists were able to restore dystrophin in four dogs that had the most common genetic mutation seen in DMD patients by making a single strategic cut in the defective DNA.
This was done by injecting 1-month old dogs with two harmless viruses that edited the genome of the dog in the cells of the muscles and heart.
Within several weeks, the missing protein was restored to the muscle tissue throughout the body, including a 92% correction in the heart and 58% in the diaphragm, the main muscle needed for breathing.
Scientists have estimated that 15% or more improvement is needed to significantly help patients.
The proof-of-concept study raises hopes that Crispr can ultimately lead to more effective treatments for DMD.
Children with DMD often die either because their heart loses strength to pump or their diaphragm becomes too weak to breathe, "said Dr. Eric Olson, one of the authors, from UT Southwestern.
The laboratory will continue to conduct long-term studies to measure whether dystrophin levels remain stable and ensure that there are no side-effects.