A Chinese researcher announced Monday that a woman has given birth to twins that he had genetically edited.
As someone who works in biotech, I have a lot of strong feelings about this. I am all for genetically engineering and modifying plant, animal, and human life, as long as it is regulated, ethical, and safe. However, that was not the case here. This was done in complete secrecy with no oversight committee. This is not how we conduct science. The following post contains my own opinions as well as some edited statements from science communicators and scientific institutions.
For starters, the researcher claims this gene editing will create HIV-resistant humans. Let’s take a look into the actual biology of what happened. Firstly, the researchers used HIV-positive sperm to fertilize HIV-negative eggs. In order to try and make the embryos resistant to HIV, the CCR5 gene (which codes for a receptor found on white blood cells) was mutated to be non-functional. However, only one of the twins was made homozygous for the CCR5 edit (meaning they received two copies of the edit) while the other was made heterozygous for the edit (they received one edited copy and one unedited copy).
It’s important to remember that people who are heterozygous for the CCR5 non-functional version of this gene are still susceptible to HIV. Aside from that, this also causes a problem because the CCR5 receptor that HIV uses to enter cells has other functions that are essential to the immune system response.
What’s so reckless about this work is that the loss of a functional CCR5 protein increases susceptibility to flaviviruses, such as West Nile virus. The researcher was attempting to make HIV-1 resistant humans, but trading one deadly virus for another, especially when flaviviruses are endemic worldwide, is an incredibly bad idea.
This is still not even mentioning the fact that he has forced one of the twins to essentially be born with HIV. To knowingly and purposefully use HIV-positive sperm to fertilize an egg is beyond disturbing. (A big thanks to The Mad Virologist for providing a lot of the information here.)
Secondly, the NIH said it best in their statement denouncing this researcher’s work: “The medical necessity for the inactivation of CCR5 in these infants is completely unconvincing. […] the possibility of damaging off-target effects has not been satisfactorily explored.”
What that means is that the use of CRISPR, which is an extremely powerful and new gene editing tool, has been known to edit genes that were not intended to be edited.
This is perhaps the most concerning aspect.
This is why we have regulations and oversight committees. We have no idea what the long term effects of these edits are going to be. Any ethical scientific institution would have needed much more evidence before beginning human trials. This is why we have animal studies and programs that can run simulations using different theoretical nucleotide sequences. To jump straight to human trials is completely and utterly unethical.
We have international standards that we abide by because we’ve seen what happens when people *don’t* abide to ethical principles. I’m of course talking about eugenics, nazi testing, the Tuskegee experiments, etc. Testing new scientific breakthroughs will never be 100% completely ethical, but we can set rules and limitations to make them as ethical as possible.
The Future Effects
Another deeply concerning aspect is the fact that these edits can now be passed on into the human germline. In other words, if these children end up reproducing they can pass these edited genes into the human gene pool. This would begin affecting every single future generation of humans. Especially given the fact that you would need two copies of the edit in order to theoretically become HIV resistant, this is highly dangerous. We would see a large increase of humans who are now much more susceptible to the flavivirus.
In my opinion, which obviously can be changed if I’m philosophically convinced otherwise, we essentially need to look at the possibility of sterilizing them for the sake of future generations and the human germline. And that in itself is a horribly unethical thing to do.
We have absolutely no idea how the researchers conducted themselves. Everything they did was kept in secret rather than them going through peer-reviewed publications. No oversight committees, regulations, or anything.
Doing science this way is completely unacceptable. I am all for the genetic modification of plants, animals, and humans, and I’ve been a proponent of that for years. But if we want to use this powerful and amazing technology, it needs to be regulated and have federal and international oversight. Without those ethical standards, scientific progress is not progress. This is not the way we conduct science. This is unethical. This is dangerous. This is not innovative by any definition of the word.