Genome editingHeritable Genome Editing Not Yet Ready to Be Tried Safely and Effectively in Humans

Human embryos whose genomes have been edited should not be used to create a pregnancy until it is established that precise genomic changes can be made reliably without introducing undesired changes — a criterion that has not yet been met by any genome editing technology, says a new report by an international commission of the U.S. National Academy of Medicine, U.S. National Academy of Sciences, and the U.K.’s Royal Society.

Heritable genome edits can be passed down to future generations, raising not only scientific and medical considerations but also a host of ethical, moral, and societal issues. Extensive societal dialogue is needed before any country decides whether to permit clinical use of heritable human genome editing — making alterations to genetic material of human eggs, sperm, or any cells that lead to their development, including the cells of early embryos — with the intention of establishing a pregnancy. 

If a nation decides that heritable human genome editing (HHGE) is permissible, initial uses should be limited to the prevention of serious monogenic diseases, which result from the mutation of one or both copies of a single gene — for example, cystic fibrosis, thalassemia, sickle cell anemia, and Tay-Sachs disease, the report says. For these cases, HHGE should only be considered when prospective parents who are at known risk of transmitting a serious monogenic disease have no option or extremely poor options for having a biologically related child who is not genetically affected without the editing procedure, due to genetic circumstances or the combination of genetic circumstances and fertility issues.  

“Any initial uses of HHGE should proceed incrementally and cautiously, and provide the most favorable balance of potential benefits and harms,” said commission co-chair Richard Lifton, president of the Rockefeller University, New York City. “For the prevention of serious monogenic diseases, the commission has defined a responsible clinical translational pathway from rigorous preclinical research that determines whether and how editing can be performed efficiently and with high accuracy, to clinical application. Countries would then decide whether an editing application is permissible, informed by preclinical data as well as broad discussion of social and ethical issues. The report provides guidance on essential elements of national and international scientific governance and oversight.”