Researchers in Dallas in the USA have published a study demonstrating the potential of a technique called genome surgery to repair mutations in genes inside a cell. However, the work is at an early stage and further research will be required before it could be used to treat people with muscular dystrophy or related neuromuscular conditions.
Researchers in Dallas in the USA have published a study demonstrating the potential of a technique called genome surgery to repair mutations in genes inside a cell. The technique is based on an enzyme that functions like a pair of molecular scissors to cut DNA in a very specific place. The researchers used an enzyme that cuts the DNA of the dystrophin gene precisely at the location of the mutation in mdx mice (an animal model of Duchenne muscular dystrophy). The separated DNA was then repaired by cellular machinery using a DNA template which the researchers added to the cells, which contained the DNA sequence but with no mutation.
The technique was tested in embryos from mdx mice which were then implanted back into the mice. This produced offspring where some of the muscle fibres produced dystrophin protein. Researchers found that production of dystrophin in just 17 percent of cells could slow the decline in muscle function.
What does this mean for patients?
Although the study has shown that the technique is able to repair mutations inside cells, it would not be used this way in the clinic since pre-implantation genetic diagnosis can already be used to identify embryos with a functional copy of a gene.
To be used to treat people with a muscular dystrophy or related neuromuscular condition, the molecular scissors and DNA template would need to be delivered to the muscle cells. Researchers believe that Adeno-associated viruses (which cause few or no symptoms in humans) may be able to deliver the components to the muscles where they are required.
Genome surgery might also address a key challenge of developing stem cell therapies. Using an individual's own stem cells to repair tissue damage would be advantageous since it would prevent the immune system killing or stopping the cells from working. However, since all an individual's cells carry the same mutations, the DNA in the stem cells would need to be repaired. Genome surgery offers a possible route to repairing the mutation in the stem cells.
Dr Marita Pohlschmidt, Director of Research at the Muscular Dystrophy Campaign, said:
We welcome the encouraging results described in this paper because they show that in principle it might be possible to repair genetic defects. Successfully repairing a genetic defect to restore production of a functional protein has the potential to be a long-lasting treatment or even a cure. In essence, it is the holy grail of gene therapy.
However, this research is at an early stage, and to develop this technique into an effective treatment for people with muscle-wasting conditions it may be necessary to combine it with other therapeutic approaches such as stem cell therapy.
It is only through your contributions that we can continue to fund the vital work that takes us closer to finding treatments and cures for muscle-wasting conditions. Donate now and help change the lives of thousands of people living with muscular dystrophy and related neuromuscular conditions.