Monday, November 9, 2015

Genetic engineering

I am Art Caplan from the Division of Medical Ethics at the NYU Langone Medical Center in New York City. Here is a bulletin from the future of medicine.

There is a new technique called CRISPR/Cas9, which allows scientists to edit the germ-line information in animals and in people. You have heard of gene therapy, but that just changes the genetic makeup of body cells. Germ-line engineering is changing the genetics in an embryo. It means those changes will be passed on to future generations.

Out of the blue, scientists in such places as the University of California (UC), Berkeley, and the Massachusetts Institute of Technology (MIT) have discovered this technique, and it is all the rage in basic science. In fact, a team of scientists at the Francis Crick Institute in London has just applied for permission to use CRISPR/Cas9 on human embryos.

There was a report last spring of a group in China that had tried this technique on human embryos, but it was published in a very obscure journal, and rightly so. They did not find any way of editing the embryos in a useful way, so it was kind of a failed experiment. I think they were looking to be first to try it on humans.

As you might imagine, this has some wonderful applications. If you could do germ-line engineering, you could get rid of diseases by engineering away the faulty genes. You could engineer out sickle cell disease, Canavan disease, Hunter syndrome, Hurler syndrome, Morquio syndrome, and maybe color-blindness and juvenile diabetes.

However, there is a big downside. We are not always sure what the faulty genes are. We are not always sure whether we edited something out that would have had a distant impact on some other traits. We are really not sure, because we have not done any animal work with this new technique. The proper way to proceed is to use it with animals and insects and see what happens there before we get to human embryos.

The other big challenge that your will hear about a lot, and probably be asked about some, is: Could you use this technique not just to fix diseases, but also to engineer better children? This concept is known as "eugenics." Everyday people may ask themselves, "Could I use germ-line engineering to make a taller, smarter, or stronger child—or whatever traits I might be looking for in my kid?"

We do not have a very good understanding still of what the genetic contribution is to these different traits. We don't know, for example, which gene or genes contribute to height, intelligence, musical aptitude, or many of the other traits that people might want. But that is all going to get filled in over the next 5-10 years. I think germ-line engineering, using this CRISPR/Cas9 technique, is going to become a major bioethical challenge.

People will be tempted to engineer their descendants—and certainly, some will try that. If you look at parents now trying to get their kids into the right nursery schools, so they can ensure admittance into Ivy League colleges or other prominent universities down the road, that kind of competitive parent is not going to hesitate to want to see their embryos edited. I think those requests are coming.

So, how do we proceed given this powerful new tool? The first step is to set out some rules for trying it in animals. Let's make sure it is safe and reliable. Let's ensure that we do not make a lot of defective animals—like we did with cloning—and that we really understand what we are doing. We would not put a drug into humans without some animal studies first. We should not be doing germ-line engineering in human embryos first before we do them in the animal embryos.

In the end, I think we might have to draw a line and say, "Look, for a while, all we are going to permit is repair of disease. You are not going to get enhancement or improvement." We have got to use these resources (and they will probably be costly) to try to fix problems. Only then can we open the door to the possibility of improving or enhancing our kids.

Maybe we will get there. Maybe we won't. But without the animal work and without some attempt to show you can repair disease, anything involving enhancement or improvement would be ethically premature. Thank you for watching.

See:  Gene editing 4/23/15

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