A Chinese scientist has shocked the world with claims he used the genome editing technology CRISPR-Cas9 to manipulate the genes of two human embryos. Twin girls were born a few weeks ago, purportedly protected from HIV when CRISPR disabled a gene that would otherwise allow HIV to enter their cells. Their father is HIV-positive.
No one knows exactly how He Jiankui, on leave from Southern University of Science and Technology in Shenzhen, did it. Scientists gathered in Hong Kong at an international summit on human genome editing will have to wait until Wednesday to hear He describe his work in more detail.
Here’s what we do know:
The claims have not been verified, but they are being taken seriously
While He has not yet released a scientific paper, his lab published five YouTube videos about its work Sunday night. In one of those videos, He strongly objects to calling children whose genes have been edited “designer babies” and answers his own question, “Why HIV?” with “safety and value,” noting that 100 million people have a “natural genetic variation” in the gene CCR5 that he altered with what he calls “gene surgery.” Also: “We will publish our full data soon.”
After He started the work, he gave official notice— on Nov. 8 — on a Chinese registry of clinical trials.
Harvard biologist and genetics pioneer George Church told STAT he’s been in contact with the Shenzhen team and seen its data. Those data are “probably accurate,” he said.
(The kind of genome editing He claims to have carried out is banned in the U.S. At the last international meeting on human gene editing, convened by the National Academies in 2015, researchers agreed to a moratorium on germline editing, or changes that could be passed down to generations that follow. In the years since that moratorium began, scientists have generally been warming to the idea that it might be worth editing embryos in order to delete a serious disease gene, say. But doing so would need to be done in a transparent way with safeguards.)
He’s own university condemned him
He had apparently been on leave from the Southern University of Science and Technology in Shenzhen. In a statement, the university said it was unaware of his work, emphasizing that it was not conducted on campus. “The University was deeply shocked by this event and has taken immediate action to reach Dr. Jiankui He for clarification.”
The announcement led to an immediate outcry among other scientists
More than 120 Chinese scientists have co-signed a letter, released on China’s social media site Weibo, condemning He’s work and calling it “a strike at the reputation and development of China’s science, especially in biomedical research,” according to a translation by Quartz. In a statement, the director of the National Institutes of Health, Dr. Francis Collins, described the claims as “unexpected and deeply troubling.”
Two CRISPR pioneers, Feng Zhang of the Broad Institute and Jennifer Doudna of the University of California, Berkeley, expressed deep concern, both about off-target effects on people whose genomes are edited and on future generations.
“Although I appreciate the global threat posed by HIV, at this stage, the risks of editing embryos to knock out CCR5 seem to outweigh the potential benefits,” Zhang said in a statement. “Not only do I see this as risky, but I am also deeply concerned about the lack of transparency surrounding this trial.”
Doudna also cited the international consensus reached in 2015. “If verified, this work is a break from the cautious and transparent approach of the global scientific community’s application of CRISPR-Cas9 for human germline editing,” she said in a statement. “This work reinforces the urgent need to confine the use of gene editing in human embryos to settings where a clear unmet medical need exists.”
At least one scientist came to He’s defense
Church told the AP that, when weighing the risks of using CRISPR against the public health threat of HIV, “I think this is justifiable.”
Church, known for contrarian views, also said that he thought it would only be matter of time before the identities of the children and their mother became known.
What about informed consent?
On consent forms that the parents were asked to sign, He called his work “AIDS vaccine development,” the AP reported, so it is not clear if the parents of the girls understood what he planned to do.
He lays out his ethical principles in one of the YouTube videos, including this statement: “No one has a right to determine a child’s genetics except to prevent disease. Gene surgery exposes a child to potential safety risks that can be permanent. Performing gene surgery is only permissible when the risks of the procedure are outweighed by a serious medical need.”
But several scientists say there are other ways to prevent HIV transmission to embryos, such such as washing sperm. And HIV is both preventable and treatable, said biologist Richard Hynes of the Massachusetts Institute of Technology. “We set out stringent criteria that would need to be met” to justify embryo editing, he said. “It should only be for serious unmet medical needs, and informed consent has to be in place.”