Gene-editing techniques such as CRISPR/Cas9 can be used to astonishing, potential life-altering effect, such as one demonstration involving a possible treatment for ALS. Researchers at Carnegie Mellon University and Yale University have now made a significant breakthrough in the technology’s usefulness — by demonstrating how gene editing can be used to treat genetic conditions during fetal development.
While so far it has only been showcased in an experiment with mice, in the future it could help treat the millions of children who are born each year with severe genetic disorders or birth defects. At present, some of these genetic conditions can be detected during pregnancy, although they cannot be corrected during fetal development.
“This is the first description of a genetic disease corrected by gene editing delivered to a developing mammalian fetus,” David Stitelman, assistant professor of surgery at Yale School of Medicine, told Digital Trends. “The gene editing reagents are in the form of peptide nucleic acids called PNA, which bind chromosomal DNA in a specific manner. The PNAs are designed to bind just upstream or downstream to a disease-causing mutation. The cell’s own editing machinery detects where the PNA has bound the chromosome and removes that segment.”
In their study, the researchers used the technique to correct 6 percent of the mutations in the gene causing beta thalassemia, a blood disorder that reduces the production of hemoglobin. Just one injection of the PNA complex into the amniotic fluid of pregnant mice caused dramatic improvements in their affected offspring. These improvements were significant enough that the mice were functionally cured of the disease.
“This work can be translated in human patients clinically,” Stitelman continued. “This approach could be used for most diseases where a known genetic mutation causes the disease. Many of these diseases are devastating and currently without cure. Our approach corrects the disease at the most fundamental level and in the most rational way. At this point, there are about 6,000 diseases that fit that description that impact about one in 200 babies.”
Possible diseases the work could help treat include neurologic diseases like Tay Sachs disease or spinal muscular atrophy, blood diseases such as sickle cell anemia, thalassemia and hemophilia, muscle diseases like muscular dystrophy, and diseases of the airway and intestinal tract including cystic fibrosis.
“We are [now] using this technology in other mouse models of human genetic disease,” Stitelman said. “We are continually optimizing the PNA/DNA editing reagents and the nanoparticles that encapsulate those agents. For future translation, we need to determine safety and efficacy in larger animals before applying this technology clinically.”
A paper describing the work was recently published in Nature Communications.