Evidence Is Mounting That Gene-Editing Human Embryos Can Have Destructive Side Effects

Errors made while editing could be passed on to future generations

In June, I reported on findings posted online by the lab of Kathy Niakan, PhD, a developmental biologist in London, which showed that the gene-editing tool CRISPR could make large, accidental edits when used in human embryos.

The paper from Niakan’s lab has yet to be peer reviewed, but the results were significant enough to catch the attention of other gene-editing scientists. As one expert, Fyodor Urnov, PhD, told me at the time, “This is a restraining order for all genome editors to stay the living daylights away from embryo editing.” In other words, the study showed that CRISPR isn’t yet safe enough to make gene-edited babies.

Just days after my story was published, two U.S. teams uploaded papers with similar findings to the preprint server bioRxiv. On October 29, one of those papers, by Dieter Egli’s group at Columbia University, was published in the journal Cell.

In the study, scientists used CRISPR on early stage human embryos in an effort to fix a mutation in a gene called EYS, which causes hereditary blindness. When they did, they found that CRISPR caused a concerning side effect: It often eliminated an entire chromosome or a large section of it. Such unintended consequences could have health effects for a resulting baby. (Here’s coverage of the new paper from the Wall…