More than four years after the first children with edited genomes were born, genome-editing techniques are still not safe enough to be used in human embryos that are destined for reproduction, organizers of the Third International Summit on Human Genome Editing announced at the conclusion of the meeting.
“Heritable human genome editing remains unacceptable at this time,” they said in a statement issued on 8 March. “Preclinical evidence for the safety and efficacy of heritable human genome editing has not been established, nor has societal discussion and policy debate been concluded.”
“Can human embryos at this stage really tolerate this kind of intervention?” asked Dagan Wells, a reproductive geneticist at the University of Oxford, UK, who also reported concerning responses to DNA breaks in human embryos. About 40% of the embryos in one of his genome-editing studies failed to repair broken DNA. More than one-third of those embryos continued to develop, he said, resulting in the loss or gain of pieces of chromosomes in some cells. That could harm the health of the child if such embryos were allowed to develop further. “These results are really a warning,” he said.
