A Russian researcher has announced controversial plans to create gene-edited babies, saying he has the skills and technology to do so and will go ahead if he can win approval. Denis Rebrikov of the Pirogov Russian National Research Medical University in Moscow says he plans to implant gene-edited embryos into women before the end of the year - if he can get permission by then.
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The proposal follows last year’s universally condemned experiment by Chinese scientist He Jiankui that resulted in the birth of genetically modified twin girls that were resistant to HIV infection.
Jiankui achieved this by using the CRISPR/cas9 gene-editing tool to delete the CCR5 gene in embryos before implanting them into a woman. CCR5 is the gene that encodes the cell membrane receptor used by HIV to gain entry into immune cells.
Rebrikov’s experiment would disable the same gene, but the researcher believes he can do a better job, claiming that his technique will provide superior benefits, pose less risk and be more justifiable. Rebrikov plans to implant the edited embryos into HIV-positive mothers to reduce the risk of them transmitting the virus to their babies during pregnancy.
When He announced the birth of the world’s first gene-edited babies, the reckless act quickly prompted an international outcry and other scientists that new about the plans beforehand were denounced for not flagging it up. Rebrikov, on the other hand, has at least shared his plans and shown willing to discuss them before proceeding.
‘The technology is not ready’
The scientific community now has the opportunity to do what they could not do with He and work with Rebrikov to discuss the risks, which many are questioning his understanding of.
Whether the experiment goes ahead or not, the fact that Rebrikov has announced the proposal shows that He is not the only scientist willing to carry out rogue gene editing in human reproduction. Other scientists are ready to proceed with human germline gene editing, which makes alterations to the DNA in sperm, eggs or embryos that will get passed on to future generations.
This is one of the main reasons He’s experiment triggered huge debate worldwide. Although many researchers agree that altering the germline could one day help to eliminate genetic diseases such as cystic fibrosis and sickle-cell anemia, much more research would be needed before it can be used to alter human beings. The pressure is now on the scientific community to stop such work in its tracks and introduce strict regulations.
However, according to Rebrikov, he has already made an agreement with an HIV center to recruit HIV-positive women who want to be involved in the experiment − a move that has troubled scientists and bioethicists.
Molecular biologist Jennifer Doudna (University of California, Berkeley) who pioneered the CRISPR-Cas9 tool that Rebrikov intends to use said:
The technology is not ready…. It is not surprising, but it is very disappointing and unsettling.”
Since He announced his controversial experiment, scientists and ethicists worldwide have been debating how to prevent rogue human germline gene editing in the clinic.
Some have called for a global moratorium on germline editing that would result in genetically modified children until it can be agreed whether its use is safe, justifiable and acceptable. Others, including a WHO advisory committee, have called for any proposals involving the editing of embryos or germ cells to be logged in a globally accessible registry.
However, the one point virtually all agree on is that, currently, pursuing any further germline editing in human reproduction is reckless and irresponsible.
Having previously worked with the preimplantation genetic diagnosis technique to help couples avoid passing on diseases to their offspring, Rebrikov knows that this method and others are better and safer options than the gene-editing of embryos.
He recognizes that cases where the benefits of editing embryos outweigh the risks are rare, but argues that one of those is the situation where HIV-positive woman are not responding well to antiretroviral therapy and are therefore at risk of passing on the virus to their babies.
However, opponents are highly critical of the plans, saying that making more CRISPR babies at this time is too risky, as it is impossible to know what unexpected effects modifying a baby’s genes may have. One recent study showed that disabling two copies of the CCR5 gene does not just protect against HIV, but may be associated with effects on cognition and lifespan.
Examining the legality of gene editing in Russia
Many countries have banned the implantation of gene-edited embryos. Most genetic engineering experiments are prohibited in Russia, but it is not clear what the regulations are in relation to editing embryos.
According to a 2017 review, Russian regulations do not clearly explain the rules on the gene-editing of embryos in the clinic. Rebrikov wants the health ministry to clarify this within the next nine months because he urgently wants to help women infected with HIV. He says he is tempted to go ahead with this even before the regulations are confirmed.
Rebrikov acknowledges that if he does proceed before the regulations are properly in place, he would be considered as irresponsible as He Jiankui, but he says he would only do this if he was certain of the procedure’s safety: “I think I’m crazy enough to do it,” he claims.
Act now on CRISPR babies. (2019). Nature. doi: 10.1038/d41586-019-01786-3.