China claims to have created gene-edited babies. What happens next?

By Amit Katwala 

Genetically modified babies are here. At least, that’s what one Chinese researcher claims. According to He Jiankui, from the Southern University of Science and Technology in Shenzhen, twin girls born in the city a few weeks ago are the first CRISPR-edited human beings.

If He’s claims are true, it would represent a huge, reckless leap forward for gene-editing. Scientists are stunned but skeptical, and have grave concerns about both the scientific validity of the work, and its ethical implications.

Why are scientists skeptical?

First, a brief science lesson. CRISPR acts like a pair of genetic scissors, allowing scientists to snip out genes from DNA and remove undesirable traits. It has huge potential for everything from ending famine to eliminating genetic diseases, but research has been cautious as those in the field navigate the technical and ethical minefield.

The CRISPR technique has been used on human embryos before, but most scientists agree that it is a long way from being refined for those embryos to be implanted back into the womb, which is what He claims to have done. “It’s been widely acknowledged that the science is not yet ready for clinical application,” says Sarah Chan, a bioethicist and director of the Mason Institute for Medicine, Life Sciences and the Law at the University of Edinburgh. “More has to be done to resolve uncertainties, and to try and understand the risks.”

There are two main scientific problems that CRISPR researchers are grappling with, and which He claims to have overcome. The first are ‘off-target effects,’ which refers to the danger of editing other genes in addition to the one you’re trying to modify. “We’re really at the early stages of research into genome editing,” says Joyce Harper, a reproductive scientist at UCL. “We just don’t know what they could do, and what this could mean for the person.”

The second problem is ‘mosaicism’, which is when only some of the cells in an organism are successfully modified. “We have no idea that effect this might have on the future person,” says Harper. “If you’re doing it for cystic fibrosis, for example, and you’ve only got the correction in a quarter of the cells, that person will still have cystic fibrosis.”

If He has made the scientific breakthroughs required to overcome these hurdles, there’s little evidence of it in the published work. This breakthrough was not reported in a peer-reviewed journal. Instead, it came to light in two medical reports posted on the Chinese clinical trial registry, and in a promotional YouTube video. “He hasn’t published anything on this at all in a peer-reviewed journal,” says Harper. “Before anyone applies this technology they should be checking on its efficiency and checking on safety so it can really be assessed by the scientific community.”

Is it ethical?

According to Ewan Birney, director of the European Bioinformatics Institute, the work would “almost certainly” be unethical in a European setting. “This type of science needs strong regulation which society can be confident in,” he wrote.

Birney also raises questions about the choice of gene He and colleagues chose to focus on. Most discussions about using CRISPR on humans have been around genetic diseases such as cystic fibrosis – things which can be screened for using current techniques. “There are currently no serious genetic diseases where pre-implementation diagnosis would not work but CRISPR would,” Birney explains.

He reportedly looked at the CCR5 gene, which is used to create protein channels that HIV uses to enter cells. People without the gene have some resistance to the disease, and some treatments use drugs to block these channels and prevent the virus from entering.

He’s study recruited couples where the father was HIV-positive and the mother HIV-negative, and used CRISPR to remove the CCR5 gene from the embryos and give them HIV resistance. However, according to Harper and others, the risk of HIV being transmitted in this scenario is relatively low, and there are other tried and tested methods for bringing the risk down further.

“We’re not talking about a terminal, incurable disease anymore,” says Chan. “To put this small, marginal benefit against the large and still unknown risks of using gene editing is not an ethical or responsible attitude.”

Chan says someone rushing ahead like this without waiting for a public consensus on the use of gene-editing technologies in humans risk setting the whole field back. “What we really need is global and inclusive public dialogue that attempts to engage with all those concerned,” she says.

Why now?

The timing of the news is interesting. It arrives just as the world’s leading geneticists are gathering in Hong Kong for the Second International Summit on Genome Editing. He is due to speak on both Wednesday and Thursday, and the scientific community is eagerly awaiting further details of his work that could verify or discredit his claims. “We need to hear his presentation, we need to see his scientific reports,” says Harper. “We need to see what he did, he has to say what he did to validate this, and really show it’s not got mosaicism or off-target effects.”

Harper has visited research laboratories in Shenzhen and seen the levels of investment in genetic technologies in China. She believes it is possible that He has actually done what he’s claimed, and that there has been a big CRISPR breakthrough in secret. “There’s nothing published at the moment suggested we’re anywhere near it, but but breakthroughs can happen overnight,” she says. “The next few weeks are going to be really interesting.”

In his YouTube video, He says he wants the technology to be used only for disease prevention, and not for manipulating things like appearance and IQ. “Gene surgery is and should remain a technology for healing,” he says. If He’s claims can be verified, Harper says the next steps are to have the safety and effectiveness of the procedure confirmed by multiple research teams before it’s used widely on humans, followed by a public and political debate, and changes to legislation.

“We need to decide who we would use it for and when we would use it,” Harper says. “Whatever happens we need to get moving on the public debate. This is going to be a fundamental change in the way we have children.”/wired