Qin Jinzhou, an embryologist who works at He Jiankui’s lab in Shenzhen, gazes through a microscope.
Image: AP

Twin girls born earlier this month had their DNA altered to prevent them from contracting HIV, according to an Associated Press report. If confirmed, the births would signify the first gene-edited babies in human history—a stunning development that’s sparking an outcry from scientists and ethicists.

Professor He Jiankui of Shenzhen, China, made the announcement earlier today in Hong Kong, informing the Associated Press of his apparent achievement and releasing an accompanying video. He claims the twin girls were born earlier this month and that he altered their DNA with the CRISPR-cas9 gene-editing tool, which he did to confer a built-in immunity to the AIDS virus. The claim has yet to be independently confirmed, and the findings haven’t been published to a peer-reviewed journal; outside experts haven’t had an opportunity to corroborate the claims, or assess the efficacy or safety of the procedure.

A BBC article describes this news as “dubious,” but there’s reason to believe the claims could be true. Back in 2016, scientists in China used CRISPR to introduce a beneficial mutation that disables an immune-cell gene called CCR5, conferring immunity by knocking out a critical receptor, or mode of entry, for the HIV virus to infect a cell. The experiment showed that someday it might be possible to deliberately endow human DNA with this desirable mutation—the key word being “someday.” Immediately after the 2016 experiment, the scientists destroyed the embryos, saying more research will be required before modified embryos can be implanted in a mother’s womb.

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Alarmingly, professor He has decided, quite unilaterally, to move ahead with this research, reportedly implanting the modified embryos into the mother’s womb—a step considered by most experts to be highly premature and reckless at this stage. Gene-editing of human embryos is sanctioned in the United States, but all embryos must be destroyed within a few days. A huge issue with this form of gene-editing is that it’s done on germline cells, which means introduced traits are heritable. Such is the case with these twins in China, who—if they are indeed genetically modified—will pass modified DNA down to any children they have. Scientists are still a long ways off from knowing if this procedure is effective and safe.

In this case, there’s good reason for doubt. The CCR5 gene is known to trigger offsetting conditions, such as a higher risk of contracting the West Nile Virus. Research suggests it also increases a person’s chance of dying from influenza. Also, CRISPR is a notoriously blunt instrument, and there’s no way of knowing if He’s procedure introduced knock-off effects, some of which wouldn’t be known until the girls reach maturity.

Details of the procedure are still scarce, such as the identity of the parents or where the research was conducted, but preliminary information acquired by AP is cause for concern.

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The AP reports that CRISPR-cas9 gene editing was done during the in vitro fertilization, or IVF, stage. Several days later, the cells of the modified embryos were checked for signs of DNA editing. Of the 22 embryos edited, 11 were used in six implant attempts. Only one worked, resulting in the twin births. In all, some seven couples participated in the procedure.

Follow-up tests suggest one of the twins had just one copy of the intended gene alteration, while the other had both. Individuals with one copy of the mutated gene can still contract HIV, but they may have an increased ability to ward off the effects of the disease. Many experts say the procedure should not have been allowed to happen, but the decision to allow the implantation of the “partially” modified embryo was an even worse indiscretion, calling it a form of human experimentation.

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Speaking to the AP, Dr. Kiran Musunuru, a University of Pennsylvania gene editing expert, said in this particular child, “there really was almost nothing to be gained in terms of protection against HIV and yet you’re exposing that child to all the unknown safety risks,” adding that the entire enterprise is “unconscionable” and “an experiment on human beings that is not morally or ethically defensible.”

Bioethicist Julian Savulescu from the University of Oxford described the experiment as “monstrous” in an interview with the BBC.

“Gene editing itself is experimental and is still associated with off-target mutations, capable of causing genetic problems early and later in life, including the development of cancer,” Savulescu told the BBC. “This experiment exposes healthy normal children to risks of gene editing for no real necessary benefit.”

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If that’s not enough, this story gets even murkier.

He, who works at the Southern University of Science and Technology of China in Shenzhen, gave the university official notice of his experiment “long after he said he started it,” AP reports. It’s not clear if the participants understood the true nature of the experiment, which was described as an “AIDS vaccine development” program. The Shenzhen university said He’s work “seriously violated academic and ethics standards,” and an investigation is in the works. He, who owns two genetics companies in China, was reportedly assisted by U.S. scientist Michael Deem, who was an advisor to He when they worked together at Rice University in Houston. Deem also has stakes in both of He’s companies.

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Condemnation of the procedure, however, is not universal among experts. Harvard geneticist George Church defended the alleged human gene-editing, telling AP that HIV is a “major and growing public health threat” and that the work done by He was “justifiable.”

A fascinating aspect of this alarming story is that He was not trying to cure a genetic disease. Rather, it was a deliberate attempt to endow humans with the capacity to ward off a future infection, namely one caused by the AIDS virus. In this sense, the procedure (if it happened in the way He is claiming), might be considered an enhancement rather than a therapy. As such, these girls may go down in history as the first enhanced humans produced by gene-editing.

Unfortunately, the brazen recklessness exhibited by He will now place a dark taint on that futuristic prospect. Yes, we may eventually use gene-editing to cure diseases and endow our species with new capacities—but such research cannot happen at the whim of rogue scientists.

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[Associated Press and BBC]