For the first time, scientific researchers successfully edited genes in human embryos to remove a mutation linked to a heart condition that can result in sudden heart failure, according to a landmark study published in the journal Nature.
Here are five things to know.
1. The gene mutation targeted in the study is called MYBPC3, which triggers the disease hypertrophic cardiomyopathy. The disease affects about 1 in 500 people and can result in sudden heart failure. Notably, the disease often incites heart failure when it affects young athletes, according to The New York Times.
2. After using sperm from men with the heart condition to fertilize eggs of 12 healthy women, researchers injected CRISPR technology — which operates as a sort of genetic scissors — into the fertilized egg and removed the mutation. They then injected healthy DNA into the egg, expecting it to replace the extracted DNA sequence. Instead, the male DNA copied the female DNA. The researchers were unsure of the mechanisms behind this interaction.
3. Out of the 54 embryos created, 36 were completely mutation-free, which is a fairly significant improvement upon natural circumstances which would have produced about 27 embryos without the mutation. Thirteen of the embryos that were not mutation free did carry some cells in which the mutation had been eliminated.
4. Researchers sought to improve the process by injecting the CRISPR technology into the egg sooner. This resulted in 42 of 58 embryos, 72 percent, coming out completely mutation-free. With fine-tuning, researchers suspect the process could reach a success rate of 90 percent.
5. While the method is far from ready for clinical use, the study represents a breakthrough in gene editing science, which poses ethical dilemmas for the scientific community. In February, a scientific advisory group assembled by the National Academy of Sciences and the National Academy of Medicine recommended new guidelines for the modifying of embryos. The new guidelines ease restrictions on the process, but urge that it only be used to address dire medical problems, according to the Times.
"We've always said in the past gene editing shouldn't be done, mostly because it couldn't be done safely," Richard Hynes, PhD, a cancer researcher at the Massachusetts Institute of Technology in Cambridge who co-led the special advisory group but was not involved with the study, told the Times. "That's still true, but now it looks like it's going to be done safely soon … [the research] is a big breakthrough … What our report said was, once the technical hurdles are cleared, then there will be societal issues that have to be considered and discussions that are going to have to happen. Now's the time."
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