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The Nash Family: Breaking New Ground in Medicine

From the WebMD Archives

Oct. 4, 2000 -- Like a lot of sick kids, 6-year-old Molly Nash has just had a bone marrow transplant, which aims to replace her diseased bone marrow with cells taken from a sibling.

What's different about Molly is that she received this precious gift from her new brother Adam, who was cleared as a donor while he was still an embryo. Molly has Fanconi anemia -- a rare and fatal disease that causes destruction of the bone marrow, where blood and the cells of the immune system are formed -- and the transplant of blood from Adam's umbilical cord raises her odds of survival by about 55%.

Doctors don't know quite yet whether the transplant actually is helping Molly produce new bone marrow, but they say the high-tech procedures used in her case -- bone marrow transplant (BMT), in vitro fertilization (IVF), and a technology called preimplantation genetic diagnosis (PGD) -- are becoming more commonplace, and offer the promise of helping others in the future.

Molly's parents, Linda and Jack Nash, endured five grueling cycles of in vitro, or test-tube fertilization, before Adam was born. Along with IVF, doctors used PGD, in which the mother's egg and the father's sperm were fertilized in a laboratory dish and the resulting embryos were screened for Fanconi anemia before they were implanted into Linda's womb.

Both Linda and Jack Nash carry the gene for the disease, and without it, there would have been a 25% chance of a second child inheriting the disorder.

PGD already is being used to screen embryos for other genetic abnormalities as well, experts say.

"PGD helps detect devastating diseases like ... hemophilia, cystic fibrosis, and muscular dystrophy," as well as Tay-Sachs, another hereditary disease that is often fatal to children, says fertility specialist Edward Wallach, MD, a professor of obstetrics and gynecology at Johns Hopkins University School of Medicine in Baltimore. "In the same way, IVF helps people become parents, and BMT helps patients fight breast cancer, leukemia, Hodgkin's disease, and sickle cell anemia."

In fact, in a case reported last year in the Journal of the American Medical Association, PGD allowed a couple who carry sickle cell trait to have twins whose healthy genetic status was known before the pregnancy. At the time, researchers said they believed the births were the first from embryos to be screened for sickle cell trait before implantation following in vitro fertilization.

But use of these technologies is somewhat different in the Nash case. The Nashes have said they planned to have another child anyway, and used PGD because they feared having one with Fanconi anemia. But Wallach and some other experts worry about the ethical implications.

"There's a disturbing utilitarian connotation overshadowing the parent's decision to have a second child," Wallach tells WebMD. "In effect, this infant has been forced to donate his stem cells, which some might consider a form of child abuse," he says. Stem cells are human cells -- such as those in an umbilical cord -- that have the potential to develop into almost any of the body's different tissues.

Another expert points out that sibling donors usually are much older than Adam.

"Most living donors are over the age of 18, but there's a few cases of minors donating kidneys to siblings," says Joel Newman, the assistant director of communications at the United Network for Organ Sharing. "But in general, child donors are usually old enough to understand the risks and benefits of the procedure."

 

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