According to a story from the Santa Cruz Sentinel, the earliest results from a critical gene editing study could offer some encouragement for those hoping to treat rare genetic diseases such as Hunter syndrome. Gene editing is a process of permanently altering a person’s DNA to correct mutations that cause genetic disorders. If the early data is something to go by, the approach could revolutionize the way that genetic diseases are treated.
About Hunter Syndrome (MPS II)
Hunter syndrome, which is also known as mucopolysaccharidosis type II (MPS II), is a type of lysosomal storage disease. This syndrome is characterized by the deficiency of a critical enzyme called I2S. Without it the substances heparan sulfate and dermatan sulfate begin to build up in the body, causing a range of symptoms. It is caused by mutations of the IDS gene, and as an X-linked syndrome, it almost exclusively affects males. Symptoms can vary widely in severity and can include distinctive facial features, skeletal abnormalities, mental impairment and disorders, retinal degeneration, hearing loss, and enlarged spleen and liver. In the most severe cases, Hunter syndrome can shorten lifespan drastically, with many patients dying as teens. Treatment involves enzyme replacement and stem cell transplants, but more options are needed, and treatment is most effective if begun promptly.
Results So Far
In the study so far, a low dose of treatment has not resulted in major changes to patients with Hunter syndrome, but with a medium strength dose, patients began to experience some changes. Most notably, levels of certain sugars measured in the urine, which are a specific biomarker of Hunter syndrome, were halved on average after a period of four months.
While this change is encouraging, it is still not definitive if the gene editing procedure was directly responsible. While these early experiments are primarily meant to measure the safety profile of the therapy, researchers are still on the lookout for signs that gene editing is effective; for Dr. Joseph Muenzer, who is leading the study, the change was “really encouraging.”
More Data Needed
The most logical explanation is that the drop sugar levels was a result of the gene therapy. Still, this doesn’t necessarily prove that the therapy has been effective, as it is unclear if bringing down the urine sugar levels alone can slow disease progression or improve the health of Hunter syndrome patients. Only further research will tell.