Scientists have successfully edited genes in a human embryo, correcting a disease-causing mutation to prevent the defect from being inherited.
The groundbreaking process, covered in a paper published yesterday in Nature, was confirmed last week by the Oregon Health and Science University, which collaborated with the Salk Institute and Korea’s Institute for Basic Science on the task.
To edit the genetic mutation, in this case for hypertrophic cardiomyopathy, researchers used a technique known as CRISPR-Cas9. The CRISPR-Cas9 technique operates as a sort of ‘molecular scissors’ which can trim away unwanted parts of a genome and replace it with new pieces of DNA.
“We have demonstrated the possibility to correct mutations in a human embryo in a safe way and with a certain degree of efficiency,” study co-author Juan Izpisua Belmonte of the Salk Institute’s Gene Expression Laboratory said in a prepared release.
The technique has been attempted multiple times in China with mixed results. To improve the chance of success, researchers introduced the genome editing components along with sperm from a male with the particular gene defect during the in vitro fertilization process.
Researchers said that the embryo used the available, healthy copy of the gene to repair the mutated part.
The study team reported that the gene correction did not cause any detectable mutations in other parts of the genome, which has served as a major concern for gene editing.
Despite the success, the technology wasn’t 100% successful, and increased the number of repaired embryos from 50%, which would have naturally occurred, to 74%. Embryos in the test were only allowed to develop for a handful of days.
“There is still much to be done to establish the safety of the methods, therefore they should not be adopted clinically,” Robin Lovell-Badge of London’s Francis Crick Institute said in a prepared statement.
While the achievement summons fears of possible heavily-edited human embryos, and so-called ‘designer babies’, the techniques are still a long way from being used in processes which result in implantation and pregnancy.
“No one is thinking about this because it is practically impossible at this point. This is still very basic research … let alone something as complex as what nature has done for millions and millions of years of evolution. It is crucial that we continue to proceed with the utmost caution, paying the highest attention to ethical considerations,” Izpisua Belmonte of the Salk Institute said.
Material from Reuters was used in this report