Screening Embryos for Disease Jenifer and Angelo Magliocco know much more about spinal muscular atrophy than they ever wanted to. The rare genetic disease killed their first son when he was only 8 weeks old. Before having another child, they used a genetic test to determine if an embryo carried the disease-causing gene.
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Screening Embryos for Disease

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Screening Embryos for Disease

Screening Embryos for Disease

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From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.

It is routine medical procedure these days for pregnant women to be offered genetic testing for their fetuses. If tests find that a debilitating or even fatal disease lies ahead, parents must decide whether to have a child who may face a short or pain filled life or to have an abortion. But in the past decade, another kind of genetic testing has emerged. It involves testing an embryo before a pregnancy even begins.

In the next half hour, we will explore the new world of pre-implantation genetic diagnosis, or PGD for short. We'll look at what it means for families fearing serious genetic illness and what new ethical questions it raises.

Joining me for our exploration is NPR science correspondent Joe Palca. Joe, how common is this new technique?

JOE PALCA: Well, Michele, at this point it's just not that common. I mean, for comparison, there's about four million children or so born in the country each year and there were only 5,000 cases of PGD in 2005.

NORRIS: So we're really talking about a very small number.

PALCA: At the moment, yes. But it's a good time to think about this, because it's a technique that offers a lot of promise and it's bound to become more popular.

NORRIS: What exactly is PGD and how is it being used right now?

PALCA: Well, to explain that I'm going to introduce you to the Magliocco family of Trumbull, Connecticut. I went to their house just before Thanksgiving. They live in a nice, pleasant subdivision. And when you walk in, the first thing you notice is that the walls of the house are filled with baby pictures.

Mr. ANGELO MAGLIOCCO: If you were to walk in this house and you didn't know, the first question you would ask is how old is your son.

PALCA: Angelo Magliocco is a barrel-chested man with dark brown hair. His son Angelo James was born on November 18, 2005.

Ms. JENNIFER MAGLIOCCO: The day he was born, there was no indication that there was anything wrong. He was moving and everything and -

PALCA: That's Jennifer Magliocco.

Ms. MAGLIOCCO: He got a clean bill of health, we got sent home and about three weeks later my husband and I were concerned with his lack of movement with his arms and his legs.

PALCA: So they took the baby to Bridgeport Hospital. One by one, doctors ruled out minor ailments that could be causing the lack of movement. What was left was unthinkable, a rare, fatal muscle disorder known as spinal muscular atrophy.

Mr. MAGLIOCCO: Every one of both of our families, clean bill of health. No signs of really anything. The last thing we suspected was, you know, to have a genetic disorder.

PALCA: But the doctors couldn't think of anything else to explain why Angelo James kept getting weaker, so they sent the baby's DNA for testing. Three weeks later, the test result came back.

Ms. MAGLIOCCO: It came back positive, which is what we thought and what we were prepared for. At that point, we only had a week with our son after he was diagnosed.

PALCA: The baby died on January 12 this year, eight weeks after he was born.

Despite their grief, or maybe because of it, the Maglioccos were determined to try again to have children, but the last thing they wanted was another child with spinal muscular atrophy. So they turned to medical science for help.

Dr. DAGAN WELLS (Yale University): Okay. It's running.

PALCA: Dagan Wells is a geneticist at Yale University. He specializes in finding genetic defects in embryos before a woman becomes pregnant. To do that, he uses pre-implantation genetic diagnosis.

Dr. WELLS: Pre-implantation genetic diagnosis is essentially a method that we have for testing very early human embryos for specific genetic disorders.

PALCA: In order to get PGD, Jennifer and Angelo first had to go through a more familiar three letter procedure called IVF, or in vitro fertilization. When we first met, Jennifer was already taking drugs that would cause her body to make more than a dozen eggs rather than the usual one per month. Just after Thanksgiving, doctors removed her eggs and mixed them with Angelo's sperm.

Dr. WELLS: And after three days they formed embryos which are usually composed of between six and ten cells, and at that point what you can do is take away just one of those cells from the embryo without causing any significant damage to it.

PALCA: The remaining cells stayed at the fertility clinic while the single cells were sent to Wells' lab across town. That was on Saturday, December 2. Two days later, I visited his lab as Wells was about to get the results.

Dr. WELLS: Okay. I'm just going to load the samples into the gel.

PALCA: The gel is what Wells uses to search DNA for evidence of the mutated gene that causes spinal muscular atrophy. Pieces of DNA from each of the single cells are sitting in small plastic tubes with numbers written on the caps.

Dr. WELLS: So you can see we have the different embryo numbers. We don't actually have an embryo number eight because that embryo wasn't developing sufficiently well to be biopsied, and similarly there's no embryo 13.

PALCA: But you do have all the way to 17.

Dr. WELLS: Yeah. A lot of embryos in this case.

PALCA: Wells is trying to find out how many of these embryos have a mutated version of the spinal muscular atrophy gene. Wells has put the DNA into a cabinet with a camera at the top.

Dr. WELLS: So I close up the door, switch on the ultraviolet light.

PALCA: The ultraviolet light shows up the DNA.

There's a tiny, tiny, tiny drop of liquid and it's just staggering to think that in there is the answer of whether an embryo is carrying a particular genetic mutation.

Dr. WELLS: Yeah, it's looking pretty good.

PALCA: As the Maglioccos wait anxiously in a fertility clinic across town, Wells is close to having an answer for them.

Dr. WELLS: We'll just print out the photographs and now we just take those back to the lab bench and try to make our diagnosis.

PALCA: Back at his lab bench, Wells pulls out a lab notebook and peers at the black and white picture.

Dr. WELLS: So essentially what we're looking for here are two different bands, and what shows us if an embryo is affected is that it will only have this band here and straightaway looking along this it looks embryo four is most likely affected and probably also embryo 12. The others look like they're fine.

PALCA: And just like that, it's done. Wells knows that the Maglioccos have nearly a dozen healthy embryos. As he's writing up his report, the fertility clinic where the Maglioccos have been waiting calls.

(Soundbite of ringing telephone)

Dr. WELLS: Yes. So essentially it looks like embryos one, two, three, five, six, seven, nine, 11, 14, 15 and 17 are all suitable for transfer. Yeah.

PALCA: Not all the healthy embryos will be transferred to Jennifer's uterus. Some will be frozen for future use in case she doesn't get pregnant this time or if they want more children.

Ms. MAGLIOCCO: We'll go through it as many times as we have to until they say we can't or until the well runs dry. So.

PALCA: How many children would you like to have?

Ms. MAGLIOCCO: Oh, I would say as many as God wants to give us. So if that's one more that's healthy, then, you know, I feel blessed. If it's twins, it'll be a lot of hard work, but that would be great, too.

PALCA: So, Michele, I guess you can see why the Maglioccos would turn to something like PGD given their circumstances.

NORRIS: Now, the Maglioccos's case seems clear enough. Many people would embrace the idea of helping a family like this who wanted to avoid having a child with a fatal disease, but how else is this procedure being used?

PALCA: Well, it's being used in a variety of different ways, and I guess there's one that's fairly controversial and that has to do with screening for what are known as cancer susceptibility genes. These are genes you've probably heard of. They can test something for the breast cancer gene, which doesn't mean you'll get breast cancer. It means you're at increased risk of breast cancer. And there's also something called the colon cancer gene and you can guess what that is making you at risk for. And the question is you can live with those, so is it appropriate to remove them?

And to give you a sense of that, I'm going to introduce you to another family. This is the Kingsbury family, and Chad Kingsbury is 33 years old and the colon cancer susceptibility gene runs in his family.

Mr. CHAD KINGSBURY: I've watched my mom pass away. Both of my uncles have passed away. My grandmother's lost all three of her kids. You know, I've got cousins that are affected. You know, I think everybody's doing well now, but it's always touch and go, and the heartache of me knowing that the possibility someday is something may happen to me and I won't be able to see everything that I want to see in my life.

PALCA: So he didn't want to pass that fear onto his children, so he and his wife, Colby, did PGD before they got pregnant. That way, their embryo won't carry this susceptibility gene. But here's the thing, Chad is alive. He's 33 years old. He's alive. And when their story appeared in the New York Times, a lot of religious bloggers just hit the keyboards. Colby says they started writing things like what's next? What else are you going to select out of the gene pool?

Ms. COLBY: They immediately want to take it to the next step and say that we're trying to create the perfect baby, and you know, and I think gosh, that's such a far leap. All we're talking about doing is making sure our daughter doesn't die from colon cancer. You know, we didn't pick the sex of the baby, we didn't pick her eye color. We don't know if she'll be good in sports, or if she'll be smart. I mean, we don't know any of those things. All we wanted to do was protect her from something that's been, I mean, literally killing off Chad's family.

PALCA: Colby says now they have a toddler, and they're planning to use PGD again.

NORRIS: Now Joe, there's an obvious conundrum here. If Chad's parents had done what Chad is proposing to do for his family, Chad would've never been born. Obviously, he's thought about that.

PALCA: He has, and he says if I'm not here, I'm not here, and so he's not terribly worried about that, but his attitude is look, I want to have a family that's part of my genetic heritage, I just don't want to pass this part along to them.

NORRIS: Are there other cases where some parents are using pre-implantation genetic diagnosis, or PGD, in order to have children that actually have certain conditions?

PALCA: Yes there are. For example, there are people with an inherited form of deafness who say look, deafness is a trait. We've lived with it all our lives. We don't see this as a disability. We would like to have a deaf child. Similarly, there are people with short stature. There's a gene that causes very short stature. People say we're small, we've lived with that, and we don't want to have a child that towers over us. We want to have a family that has this condition. So it can actually be used to select things in rather than exclude something.

NORRIS: Who decides what's an acceptable application for this technology? Are there regulations? Are there laws? Is there any sort of medical code of ethics on this?

PALCA: Well, there's, yes, there's certainly a code of ethics, but it varies because each hospital and each clinic pretty much gets to make up their own rules. There is no overarching standard and if, for example, you believe you've found a gene for carpal tunnel syndrome and somebody says look, it's in my family, and I want to get it out, if somebody's willing to do that, you can have PGD for carpal tunnel syndrome.

NORRIS: And what about laws or regulations?

PALCA: No, there's nothing - I mean, there's just nothing that really specifically deals with this in a - that covers it in a very specific way.

NORRIS: Joe, I was surprised at how open these families are, even though they're being pulled into this robust and quite prickly moral debate in this country.

PALCA: They are, because they feel very strongly that they want people to know that there's a way to avoid a problem, a genetic problem, and they also feel very strongly that there is a difference between an abortion and discarding an embryo, because that's what they have to do. They have to discard an embryo that has a particular condition.

But they see that as a morally different thing because as you heard, these are - at least in one case, you have very religious people. People have different opinions about this, but the people we've talked to who have accepted this technology obviously see a difference between a fetus and an embryo that hasn't been implanted in a woman.

NORRIS: This is NPR science correspondent Joe Palca. This is interesting stuff, Joe. Thanks so much.

PALCA: You're welcome.

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