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Two genetic experts claim that the controversial human gene editing experiment conducted by the Chinese scientist He Jiankui was not only unethical, but that it was also deeply flawed from the point of view from a scientific point of view. The experiment, they said, will probably not work as planned, and the two girls produced by the project are now facing uncertain health risks.
The authors of the new commentary article on PLOS Biology, geneticists Wang Haoyi and Yang Hui of the Chinese Academy of Sciences (ACS), did not mince their words, as they strongly criticized the l & # 39; Gene modification experiment conducted by the Chinese geneticist He Jiankui.
"[We] I believe that there is no sound scientific reason for performing this type of genetic modification on the human germline and that its behavior, as well as that of its team, is a flagrant violation of Chinese regulation and consensus international scientific community has reached »authors. "We strongly condemn their actions as extremely irresponsible, both scientifically and ethically."
At the second International Summit on Gene Publishing held in Hong Kong last November, he was shocked by the world, announcing the birth of twins whose DNA he had altered with the help of the CRISPR / Cas9 gene editing tool. Working with embryos, he deactivated the CCR5 gene, which encodes a receptor that, along with another receptor, serves as a gateway for the HIV virus to enter and infect white blood cells. The goal of the project was to confer integrated genetic immunity to the virus. He said the procedure was medically necessary since the girl's father was HIV-positive.
Wang and Yang challenged the reason for the project and how the experiment was conducted. Although full details of the work have not yet been released, the authors indicated that the experimental design and data presented at the Hong Kong summit "revealed a serious misconduct both scientifically and ethically. " The authors felt the need to write the comment. article "because we believe that a responsible review and discussion of this event require a good understanding of the scientific facts."
The procedure was not medically necessary, they said, because an HIV infection at the design stage can be avoided by keeping to established AHR protocols. With regard to the risk of infection after birth, "avoiding the potential risk of HIV exposure is enough for most people," wrote the authors, adding that "the edition of Early embryos have no benefit for babies, while posing potentially serious risks on many fronts. "
These "multiple fronts" included a poor understanding of how the absence of the CCR5 gene could affect Asian individuals, particularly how the introduced allele, or mutated gene, could lead to unanticipated health risks. This seemingly fortuitous mutation can occur naturally and scientists have studied the resulting effects for Europeans, who appear to be in good health for the most part. That said, the CCR5 mutation does not protect individuals from all strains of HIV. In addition, the effects of this mutation have not been studied in detail in Chinese populations. Therefore, "it is very difficult to predict the risk [CCR5 allele] in a Chinese genetic context, "wrote the authors.
"Although he claimed that there was a long-term health monitoring plan, there are no details about who will fund it or take responsibility for any medical problem" they wrote.
Wang and Yang described the quality of the science used by He as "poor quality". During his presentation in Hong Kong, for example, the scientist said he used data on the inhibition of CCR5 in mice to determine if the deleted gene would cause adverse effects. genetic, physiological or behavioral consequences, "as it says in the slide show.
"It's absurd," Wang and Yang wrote, adding that "it was not possible to answer this question simply by comparing the histological staining of four different tissues without any quantification and by performing two simple behavioral tests in mice ", adding that science was" very complex ". poor and superficial. "
Among the other problems exposed by Wang and Yang, there were some experiences that could not be replicated, and a lack of attention given to the potential problems produced by untargeted mutations (in which CRISPR / Cas9 might have altered by inadvertence of other genes) and the potential for mosaicism. (in which an individual has acquired several distinct genomes). Wang and Yang wrote that the approach used by He was not sophisticated enough to detect any off-target mutations, and that he "probably underestimated the rate of mosaicism." and the risk of introducing harmful genetic alterations ".
The authors concluded their commentary by urging the international community of scientists and regulators to "launch as soon as possible an in-depth discussion to develop the criteria and standards for genome modification in the human germ line for the purpose of reproduction". Jurisdictions can then pass laws and set up the necessary institutions for monitoring and enforcement, the authors wrote.
"I agree 100% with the authors," wrote Brendan Parent, bioethicist at the NYU School of Medicine, in an email to Gizmodo. "He Jiankui has violated all the principles of responsible research in order to be the first to try. He did not go through the proper channels of approval, his informed consent process for the parents was misleading and his justification was false.
Parent, who is not affiliated with the new comment, said that parents living with HIV could have a child unaffected by the virus through the use of in vitro fertilization (IVF) and testing Preimplantation Genetics (PGT), which involves screening for disease in the embryo. before implantation.
"We do not know exactly what types of health risks these children will suffer without knowing how genetic manipulation affects development and whether we are a mosaic of the CCR5 gene intended to be deleted, which means that they each have a partial expression of the gene "Parent told Gizmodo. "Furthermore, we do not know what the simple process of germline modification does to a human embryo, even if it was a technical success for the intended gene modification."
The good news about all this is the overwhelming consensus that it has done a bad thing and that measures need to be put in place to prevent such a situation from happening again. Hope this consensus will lead to action.
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