The powerful gene editing technology CRISPR is one step closer to treating a human disease. Science, reports that a UT Southwestern Medical Center team reported they had successfully used CRISPR to correct the genetic defect responsible for Duchenne muscular dystrophy in four beagles bred with the disease-causing gene.
People born with the disease are often eventually confined to wheelchairs as their muscles continue to weaken, and in the later stages, many rely on ventilators to breathe as their diaphragm muscles stop working. Eventually, they develop heart and respiratory failure.
The team “fixed” the mutated dystrophin gene by splicing out an offending section of the gene using CRISPR. The gene editing technology, discovered in 2012, can cut out sections of DNA at precise locations (and also introduce new DNA as well). In the case of Duchenne, simply snipping out a section of the mutated dystrophin gene allows the gene to make enough of the proper protein that muscles need to function.
The results were jaw dropping.
The muscle cells in various parts of the dogs bodies, including the heart and diaphragm, were churning out healthy dystrophin protein at anywhere from 3% to 90% of the normal levels eight weeks after injection. Because Duchenne affects deep organs like the heart and respiratory system, finding a way to deliver CRISPR more widely, without repeated and multiple injections, is preferable.
The study is the latest in an encouraging string of results in applying CRISPR to treat human disease. Researchers have also successfully used the gene editing technology to splice out HIV from both infected human cells in the lab and in living mice and rats, and are close to beginning trials to blood disorders like beta thalassemia and sickle cell anemia. Scientists have even corrected a genetic heart defect in embryos in the lab, which were not allowed to develop further or be implanted for ethical reasons.
Duchenne, often diagnosed before people start to notice symptoms of muscle weakness, might be halted in its tracks before important skeletal, heart and breathing muscle are damaged beyond saving. A CRISPR-based therapy may be most effective in treating young people recently diagnosed with the disease, to prevent them from ever experiencing the symptoms of Duchenne.
The hope is that if those animal studies and human trials prove this technique is safe and effective, CRISPR could potentially lead to a cure for Duchenne. Note that this is a cure, not a treatment. All of the other therapies so far for Duchenne muscular dystrophy have treated the symptoms and consequences of the disease. This is going right at the root cause of the genetic mutation.
"Today," "I will be lecturing about the liver and spleen."
"Damn, if there's one thing I can't stand it's an organ recital."
