Since the 1970s, genetic screening has been a standard practice during pregnancy. The goal of this kind of genetic testing has historically been to understand the likelihood an embryo carries a heritable disease, the classic example being the recessive genes for autosomal recessive disorders like cystic fibrosis, sickle cell anemia, and Tay Sachs, or tests that determine developmental disorders like Down Syndrome. This allows parents to make informed choices about ending pregnancies and planning ahead for potential issues.
But as genetic technologies develop — and gene editing becomes more widely practiced — the possibilities are not limited to observation. As Dr. Robert Klitzman writes in Designing Babies: How Technology is Changing the Way We Create Children, genetic testing in the context of IVF is already giving us a glimpse of the ways in which the proliferation of new technologies could affect the genome of future children and future generations. And it’s not all good news.
Klitzman, Director of Columbia University’s Masters of Bioethics Program, suggests that progress has not been accompanied by adequate oversight or regulation. What are the limits of genetic screening, genetic testing, and gene editing technologies? The answer has as much to do with what risks are deemed acceptable and what risks are not. Designer babies are no longer the stuff of science fiction, but would-be parents aren’t exactly in a DNA Build-a-Bear. A transition is underway and Klitzman believes that parents need to understand the bleeding edge of what’s possible to have the necessary context to understand the technologies they are using — even in the process of basic screenings.
Fatherly spoke to Dr. Klitzman about the current state of genetic testing and the potential risks of emerging technologies.
Expecting parents likely understand one side of genetic testing: screening for heritable diseases. But new technologies and new discoveries mean that we can do more with genetic information and with genes themselves than ever before. So what are the limits of the current technologies?
A few years ago people thought we’d find the ‘cancer gene’ or the ‘fat gene.’ But now we know that for most common diseases and most complex traits there are many genes involved. Sure there are certain genes that increase the risk of cancer from, say, five or 10 percent. But in genetic screening for diseases people should realize that, for a lot of diseases, the world is more complicated than just screening an embryo.
So, it’s the old debate: nature or nurture? The answer is both. For a lot of traits, genetics explains the part but not all of the risk of the disease. So you may undergo genetic testing or you may screen embryos and the child may still get certain diseases. It’s not always foolproof.
But it’s better than nothing.
It’s important for parents to get tested to see if they have recessive conditions particularly if it’s in their family. If anyone has cystic fibrosis in their family, they should be tested to know. If they’re a carrier, they should see if their spouse is a carrier. If anyone has breast cancer in their family, they should be tested to see if they have that mutation. I think people with sickle cell disease should be tested for that. I think any woman who is over 35 should have the embryo tested for down syndrome and other chromosomal abnormalities. So I think there are certain diseases.
But, through evolution, most diseases for which there is a very predictive genetic test tend to be rare. If there was a terrible gene that was wiping out people, it wouldn’t be getting passed on. The only genes that get passed on are not going to be from really terrible mutations because they would kill the people and by and large they wouldn’t have any kid.
It’s interesting that you point out the limits of genetic testing technologies because you’re also a strong advocate for increased access.
I think insurance should pay for genetic testing. If a couple is concerned because their cousin has cystic fibrosis or someone in their family has sickle cell disease and wants to get tested, that should be covered. It may not be covered now so I think that’s another set of policies that need to change. And part of that I think there needs to be more genetic counseling, which insurance also doesn’t cover. The laws haven’t kept up with the technology. Our technologies advanced way ahead of our legal system and our duty to understand and figure out what to do with that of ethical legal and social questions involved.
A lot of the thornier issues you write about involve preimplantation genetic diagnosis, which is genetic testing post-conception and prior to pregnancy in the context of IVF. How are the decisions made by would-be parents undergoing PGD different than the decisions being made in the context of normal genetic testing?
Right now, we genetically screen embryos. When a couple undergoes IVF, let’s say they create eight embryos. Doctors could say, ‘These four are the girls, these four are the boys.” Now, let’s say a family has a history of breast cancer or the mother has the BRCA gene which carries breast cancer. The doctors could say, ‘These three embryos have breast cancer gene these five don’t.’ And the couple can choose the ones that don’t.
Also, increasingly couples can say, ‘Well, I just want a boy.’ And that creates a number of ethical challenges as opposed to letting Mother Nature do whatever it would do.
So there’s potential in that specific context to take action in a way that’s not possible in typical screenings. How much of that action is embryo selection versus actual gene manipulation?
We can take genes out. There’s a gene associated with Huntington’s disease or the BRCA breast cancer gene. We now have the technology to take them out. But these technologies are still in an experimental phase. And I’m concerned that they’ll soon be made fairly widely available even though there still may be risks involved and people may or may not fully appreciate those risks.
A few years ago, a doctor in China used CRISPR to edit the genes of twin girls. That opened brought a lot of criticism but also raised awareness of what can be done with this technology.
That’s right. So what Dr. He Jiankui did is that he worked with fathers who had HIV. There was a concern that the father could potentially pass HIV onto the child. And so he took the embryo and disabled the CCR5 gene that is involved in letting HIV get into a cell. The problem is that when you disable that gene, the risk of getting HIV goes down but the risk of getting influenza getting in goes up as do other risks.
DNA consists of three billion molecules. Each of us is a shelf of books in an office that has three billion letters in them. Well, if you go in and rip out some letters, you want to make sure you rip out the right ones. And so it looks like Dr. He didn’t do it so precisely. So in fact what he said he took out wasn’t exactly what he took out. In other words, if a child is born and missing part of the DNA, that part might be the next gene that’s involved for, say, brain development or something like that.
You need to be very, very careful.
Presumably, the ethical questions get more complicated when gene editing becomes a more widely available procedure….
Until 60 years ago, we didn’t even know what DNA did. We now have the ability to identify genes and we’re increasingly finding genes that are associated with not only various diseases but also human traits — those associated with blonde hair and blue eyes, those associated with height and perfect pitch.
I think CRISPR probably will be used for people wanting or not wanting certain socially desirable or undesirable traits in their children.
A Gattaca situation.
This interview has been condensed and edited for clarity.