Scientists used the gene-editing tool CRISPR to successfully remove a deadly heart disease mutation from viable human embryos. Though the embryos were terminated three days after the gene was removed, the success suggests we may soon be able to remove certain devastating and deadly diseases from the human genome.
A new study published online in Nature reported that scientists removed a genetic mutation that causes hypertrophic cardiomyopathy, a genetic heart condition that causes sudden death in otherwise healthy individuals, along with several other genetic heart conditions. According to the study, the procedure was 72 percent successful, and 42 of the 58 embryos involved in the research ended up without the faulty gene five days following incubation, IFL Science reported.
"This is the first that has been demonstrated as safe and working," study co-author Juan Carlos Izpisua Belmonte told CNN. "All cells of the embryo were corrected. It seems to be working from these samples that we have chosen, but we need to do much more basic research with many other genes."
The researchers used CRISPR, a gene-editing technique, to remove the mutation that led to the heart condition from human embryos. In addition to this, the cells’ DNA-repair mechanisms were replaced to ensure that cells did not replicate the harmful gene during cell division, CNN reported. The embryos in the study were created from sperm of men known to carry the heart disease gene, and eggs from healthy women known not to carry the gene.
Although this is not the first time that researchers have attempted to edit faulty genes from human embryos, it is the largest study of its kind, researchers noted. Chinese researchers are also working on similar projects.
The idea of editing human genes often brings images of eugenics to mind, replacing less desirable traits with more desirable ones. So far, the main focus of gene editing is prevention of inherited disease. For example, the mutation edited out in this study is associated with a number of inherited heart conditions, including left ventricular noncompaction, familial dilated cardiomyopathy, and familial hypertrophic cardiomyopathy, CNN reported. What’s more, hypertrophic cardiomyopathy is considered to be the most common inherited heart condition and affects around one in 500 Americans, the Centers for Disease Control and Prevention reported.
The embryos were only allowed to mature for three days before they were disassembled for further study, CNN reported. It is still too early for scientists to consider allowing these embryos to mature into a fetus. However, the success does hint that the elimination of certain deadly genes from our genome is in the near future. Of course, this comes with its own risks as many genes have more than one role. For example, the gene that leads to heart disease is also associated with human fertility. It may be that the risks of removing a faulty gene may not become clear until it’s too late.
Source: Ma H, Marti-Gutierrez N, Park SW., et al. Correction of a pathogenic gene mutation in human embryos. Nature . 2017