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Has a Chinese chancer won the gene-editing race?

Credit: Getty

November 28, 2018   5 mins

Human genome editing was always going to happen, eventually. And it was probably going to happen first in China, where there is far less stigma around the idea. The Chinese word for “eugenics”, yousheng, has entirely positive connotations; not smoking while pregnant, for example, is considered yousheng. The Chinese public has embraced preimplantation genetic diagnosis, screening embryos for health characteristics and aborting them if they have, for instance, deafness or Downs syndrome, to a far greater extent that the West has.

So it’s not a huge surprise that, apparently, twin girls have been born in China with a specific gene, CCR5, eliminated, using the technique CRISPR/Cas9. I say “apparently” because it’s all a bit murky: there are medical documents posted online, but they’re not peer reviewed, the scientist involved – He Jiankui of the Southern University of Science and Technology, in Shenzhen – has declined to speak to the press (although he has now addressed a conference in Hong Kong), and everyone has residual memories of that guy who claimed to have successfully performed a head transplant and that other one who reckoned he’d cloned humans. Plus, some of the organisations apparently involved say they don’t know anything about it. But it’s plausible. At least one geneticist I’ve spoken to thinks it’s real.

It may not be a surprise, but nor is it a good thing. In Britain, human genome editing is regulated by the Human Fertilisation and Embryology Authority (HFEA). It’s a good and far-sighted organisation, willing to allow the use of new technologies when they are shown to be safe and effective; Britain became, in 2016, the first country to allow mitochondrial donation, the so-called “three-parent baby” technique, to prevent devastating mitochondrial disease.

The HFEA allows human embryos to be edited. But they have to be destroyed after 14 days, and can’t be implanted. That’s not out of some misguided fear of playing God: if it could be shown that the procedure could reliably and safely prevent disease, I’m pretty sure that the HFEA would back it. But it can’t.

That is, in short, because as yet it’s not safe, or reliable. There are frequent “off-target effects” – basically, unwanted mutations introduced by the procedure – and “chimeras”, where some of the cells in the embryo are successfully edited, but others aren’t, so you end up with a patchwork embryo, half-full of cells which still have the gene you wanted to remove.

These problems mean that only about 20-30% of attempts to edit human genomes are successful, at least on trials of CRISPR for thalassaemia, which similarly involved knocking out a single gene. Those embryos, of course, were destroyed at the 14 day mark.

It may be that, soon, those odds improve. And then it could well be ethical to, cautiously, do the first human trials. The Oxford bioethicist Julian Savulescu says that those first trials should be in embryos with “otherwise lethal catastrophic genetic mutations who are certain to die”. Then the edits might save the lives of the babies, when they are born.

That is not the case with these Chinese babies. They were, according to the literature that has been released, entirely healthy. The procedure might have introduced some hidden mutation that turns out, later, to be deadly or life-limiting.

Even so, you could perhaps imagine that there were some mitigating factors. At least they’ll have done something that will improve their lives. But the answer is: not really. If all the claims that the scientists make are true, and if it’s all gone perfectly, then the twins are very unlikely to see the faintest benefit, ever.

That’s because CCR5, the gene that has apparently been eliminated, is involved in resistance to HIV. (The twins’ father apparently has the virus.) In one twin, both copies of the gene have been removed; in the other, just one, meaning that she may still be susceptible.

This makes it a preposterous thing to do. HIV is an extremely well-controlled condition. It is easy, using modern antiretroviral drugs, to render an HIV-positive person entirely incapable of transmitting the disease. What’s more, removing CCR5 – if it works at all, which is not entirely clear – only protects against one strain of the disease. It is highly unlikely that the two babies would ever get HIV, and if they did, they could be treated and live a normal life with a normal life expectancy. Instead, if all this is real, their lives and health have been put at considerable risk, for no discernible benefit.

I don’t know why Dr He has done this, if he really has. It’s worth noting that he owns two genetics companies, so worldwide publicity probably isn’t a bad thing for him.

But whether or not it’s real, there are two likely outcomes from all this. One, it puts a big stain on the reputation of good, sensible human genome editing, as goes on all the time in the UK under the auspices of the HFEA. The Crick Institute’s Kathy Niakan (who has also condemned the China story), who is working on mitochondrial donation, is also looking into how genome editing could help avoid miscarriages in early pregnancy. That is work which, if successful, could avoid huge amounts of human misery. But it’ll be that much harder to sell to the public if everyone’s first thought, when the term “human genome editing” is mentioned, is of some chancer’s needless publicity stunt.

And, perhaps more importantly, this is one of those fields where everyone’s best interests are served if it is treated as a worldwide collaboration, rather than a race. Cautious advances, carefully checked in the court of scientific evidence and under the eye of review boards and ethicists, could lead to a situation where human genome editing benefits everyone. A mad rush to be The First Person To Do It (or, now, maybe, the second) could lead to people cutting corners, to mistakes being made, to some poor child being born with some awful, unnecessary condition.

The idea of human genome editing is far less taboo in China than here, as I said. But this rogue behaviour hasn’t gone down well there, either. The university where Dr He works has placed him under investigation for ethical breaches, and more than 120 Chinese scientists have criticised him in an open letter. They worry that the country has a reputation for cutting ethical corners on genetic research; that’s especially true since 2015, when Chinese scientists became the first to edit genes in human embryos.

As the Atlantic reports, the country’s geneticists have since taken pains to demonstrate that they take scientific ethics seriously, but there are still suspicions that the government and its universities turn a blind eye to reckless behaviour. Robust investigations of the He Jankui research would go some way to allaying those fears. Since Dr He has now said another child may be on the way, it’s best that happens fast.

Human genome editing was always going to happen, eventually. It’s just a shame that it happened now, when we’re not very good at it, and that it was deployed to fix something that didn’t need fixing. This is a powerful tool that can improve humanity’s future; hopefully, this silly stunt won’t slow that down.

Tom Chivers is a science writer. His second book, How to Read Numbers, is out now.


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