Chinese study on CRISPR could increase risk of premature death of twins, study finds

The first genetically modified babies in the world raise new concerns.

According to a study published Monday, it would appear that the genetic variation that a Chinese scientist was trying to recreate when he had revised the binoculars DNA could be more harmful than useful for general health . The study, in Nature Medicine, involves the DNA of more than 400,000 people.

"It's a telling tale," says Rasmus Nielsen, a professor of integrative biology at the University of California at Berkeley, who led the new study.

Chinese scientist He Jiankui announced last fall that he had created binoculars from an embryo whose DNA he had altered in his laboratory with the help of the powerful CRISPR gene modification tool.

He said he had modified a gene called CCR5 to protect girls from the AIDS virus. But there is also evidence that CCR5 variation has other effects, such as making people more vulnerable to West Nile virus and influenza.

"We know that this has many different effects, the question is: Is it globally beneficial or detrimental to have this mutation?" Nielsen says. "It was not known."

Nielsen and his colleagues analyzed more than 400,000 people whose genes and medical records are stored in the British biobank in Britain.

Overall, the researchers found that those who owned two copies of the CCR5 variation were about 21% less likely to live up to age 76, report Nielsen and his colleagues.

"What we found was that they had significantly increased mortality," says Nielsen. "It's pretty substantial – we've been pretty surprised that the effect is so important."

The reason is not entirely clear, but Nielsen thinks it's probably because of increased vulnerability to the flu.

"It's a likely explanation," says Nielsen.

The results highlight why it was premature for the Chinese scientist to do what he did, Nielsen said.

"There are many reasons why we should not be creating CRISPR babies at this stage, and one of them is the fact that we can not really predict the effect of mutations. that we induce, "says Nielsen.

Other scientists are in agreement.

"It's a lesson in humility," said George Daley, the dean of Harvard Medical School.

"Even when we think we know something about a gene, we can still be surprised and even surprised, as in this case, to discover that a gene that we thought was protective might actually be a problem, "says Daley.

Daley notes that, according to data presented by the Chinese scientist last year, he apparently has not even managed to modify the gene as expected. It is therefore far from clear how the changes he has made will affect girls.

"We do not even begin to understand the impact of these deletions on the original intent of preventing HIV infection. The experience in China has been a failure, not only ethically, but also scientifically, "said Daley. .

Some scientists argue that the genetic modification of the human genome could possibly be useful.

"I think we should always be concerned about the unintended consequences of any new technology, not just the editing of genes and embryos," said George Church, professor of genetics at Harvard, who was less critical of his respect.

"Every new technology has unintended consequences, the first monoclonal antibodies were almost deadly, the first gene treatments were actually fatal, all kinds of transport was and still are deadly, it's all about benefits and risks," says Church. .

But many scientists, bioethicists and advocates fear that other scientists will prematurely abuse technology.

Shortly after his announcement, the Chinese scientist said that he had been contacted by at least one infertility clinic in Dubai to congratulate him and ask him if he wanted to teach them how to do what he wanted. He had done, according to William Hurlbut, a scientist and bioethicist at Stanford. in contact with him.

"They asked him if he would come up with some sort of lesson or tutorial so that this technology could be used in their clinic," Hurlbut said. "You can see from that that there will be an immediate adoption for the implementation of this."

Any modification to human embryos could be passed on from generation to generation, which is why this type of genetic manipulation has long been considered forbidden.

"I think we are facing a very serious problem as a species here," said Hurlbut. "It's not like other technologies.It's not like you're dealing only with an individual patient.You are now dealing with the entire human gene pool."

But Hurlbut, while stressing that he repeatedly tried to persuade He not to do what he did, said that he had good intentions.

"I think it's a bit unfair that he's qualified as an outstanding scientist," says Hurlbut. "It's not really who he is."

Hurlbut said that he was really trying to help prevent the spread of HIV in China, where the disease remains very common in some places and extremely stigmatized.

"I do not justify what he did, but I think it's more understandable to take the time to talk to him, what I've done," says Hurlbut. "I do not approve of it – and I've always told him I do not approve of it – but on the other hand, it's more understandable."