More CRISPR gene-edited human babies could be on the way

A Russian molecular biologist is seeking approval to genetically modify human embryos, but scientists are still concerned the technology isn't ready.

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Jackson Ryan
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The first gene-edited human babies were born in 2018.

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A Russian molecular biologist plans to edit human embryos using the incredibly powerful gene-editing tool known as CRISPR in a similar fashion to Chinese researcher He Jiankui, according to a report by Nature.

He came to prominence in November after announcing his team had edited two human embryos, resulting in the birth of twin girls -- the first gene-edited human babies. After revealing his work at the Second International Summit on Human Genome Editing, He was quickly condemned by his contemporaries, leading to his dismissal from his post at the Southern University of Science and Technology in Shenzhen, China, and an investigation by Chinese government officials.

He used CRISPR to edit a specific gene -- CCR5 -- which has been shown to allow the AIDS-causing virus HIV to enter cells. He found HIV-positive fathers and HIV-negative mothers in which to implant CRISPR-edited embryos, justifying his actions by explaining how deleting CCR5 would prevent HIV transmission to the fetus. Experts have rebutted this idea, saying there are other ways to prevent HIV transmission in pregnancy and He cannot be sure that deleting the gene would even prevent such infection.

"Targeting CCR5 in human embryos is highly questionable," said Gaétan Burgio, a geneticist at the Australian National University in Canberra. He notes that, from a practical point of view, it is much easier to recruit volunteers for such experiments, as opposed to those suffering rare genetic diseases. 

Now Denis Rebrikov, a Russian scientist at the fertility clinic of Moscow's Kulakov National Medical Research Center for Obstetrics, Gynecology and Perinatology, has told Nature he plans to make the same genetic changes using a tweaked methodology. Unlike He, Rebrikov will first seek approval from the Russian health ministry and two other government agencies before beginning his experiments. Still, researchers are concerned.

Rebrikov's plan is slightly different from He's, recruiting HIV-positive mothers. Nature reports he already has an agreement in place with one HIV clinic in Moscow. The researcher suggests he has made improvements to the notoriously finicky CRISPR editing technique, which has previously been shown to make unintended gene edits outside its target area.

The gene-editing of human embryos has been controversial, with a global moratorium suggested by some of the world's foremost CRISPR experts and ethicists. Editing an embryo introduces genetic changes into the gene pool -- but the technology hasn't been refined enough to justify such changes just yet, they say.

"The technology is far from ready," said Burgio. "I don't see any gene worth targeting to date and for the next couple of years as long as the technology is not ready."

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