'Selecting' Siblings to Help Sick Kids

Center Combines Fertility Technique, Tissue Typing to Choose Children With Lifesaving Stem Cells

From the WebMD Archives

May 4, 2004 -- Nine-year-old Molly Nash's life was saved by the birth of her baby brother, Adam.

Adam, now 3 1/2, was conceived by in vitro fertilization. Genetic testing of him as an embryo proved him to be a good tissue match for his sister, who was fighting a rare and potentially fatal blood disease. And doctors have delivered five more children who were hand-picked to help save the lives of older siblings.

Five weeks after Adam was born, stem cells from his placenta were transplanted into Molly, and now the once desperately ill little girl is healthy and happy. She has little memory of the illness that almost took her life.

"She was on a lot of pain medication, so she doesn't really remember," mom Lisa Nash says. "She knows that Adam gave her some blood that made her feel better. And Adam knows even less than that. When the time is right we'll tell them, but I don't know when that will be."

But could some parents abuse the ability to choose the genetic aspects of their children?

Five More Births

Lisa Nash and her husband, Jack, were the first couple to attempt genetic testing at the embryo stage to ensure that their second child would be a good tissue match for their first. Researchers at Chicago's Reproductive Genetics Institute, where they had the procedure, report their experience with nine similar cases in the May 5 issue of TheJournal of the American Medical Association.

Preimplantation genetic diagnosis, as it is called, has been used for more than a decade by couples who turn to in vitro fertilization to avoid passing on serious inherited disorders to their children. More than 100 different genetic conditions are considered worthy of preimplantation genetic diagnosis, but the Chicago fertility researchers are the first to combine tissue typing with the procedure to ensure a donor match for an existing child.

The nine couples in the study had children with leukemia or a rare but potentially fatal form of anemia. Both conditions are best treated with stem cell transplantation from a matching donor.

Researchers removed DNA from 199 eight-cell embryos following in vitro fertilization and analyzed them for tissue compatibility with the sick children. Twenty-eight matching embryos were transferred, resulting in the birth of five healthy children whose tissue matched that of their siblings.

If the couples had conceived naturally, they would have had a 25% chance of giving birth to a child whose tissue matched his or her sibling.

"Prior to this technology, tissue matching could only be done after implantation," study co-researcher Anver Kuliev, MD, PhD, tells WebMD. "Obviously interrupting the pregnancy because the fetus is not a match is a poor option."

Designer Kids?

While there are legitimate "Brave New World" concerns surrounding new technologies that allow parents to select the traits of their children, bioethicists contacted by WebMD say they have few concerns about using preimplantation genetic diagnosis to avoid life-threatening genetic illnesses and possibly save sick family members.

In an editorial accompanying the study, Norman C. Fost, MD, addressed the criticism that as preimplantation genetic diagnosis becomes more refined, people may use it to select trivial traits like eye color. This "slippery slope" argument, he notes, can be made with just about all new technology, "since new technology almost always has undesirable consequences." Fost directs the program in medical ethics at the University of Wisconsin and is the former chairman of the American Academy of Pediatrics Committee on Bioethics.

Ethicist Josephine Johnston says that given the expense and poor success rate of IVF, it is unlikely that couples will choose it over natural conception for frivolous reasons. Johnston is an associate for ethics law at the Hastings Center for bioethics research in New York's Hudson River Valley.

"With the trauma and uncertainty involved with IVF, people certainly aren't clamoring to do it if they can conceive naturally," she says. "But the concern about designer children may become more real if the success rate for IVF improves."

'The Best Outcome'

Lisa Nash says she and her husband heard all the criticisms but consider preimplantation genetic diagnosis a godsend that gave the Colorado couple the option of having a desperately wanted second child that could, as an added bonus, help make their first child well.

It took them five IVF attempts, at a cost of more than $80,000, to have Adam and two other attempts to have a third child 13 months ago.

"My worst fear was that I would have other kids who would only know Molly through pictures, or that my husband and I would have never had any other children because of the risk of passing this illness on," she says. "Out of the possible scenarios, this technology gave us the best outcome imaginable."

Show Sources

SOURCES: Verlinsky, Y. The Journal of the American Medical Association, May 5, 2004; vol 291: pp 2079-2085. Anver Kuliev, MD, PhD, Reproductive Genetics Institute, Chicago. Josephine Johnston, associate for ethics law in society, Hastings Center for bioethics research, Garrison, N.Y. Norman Fost, MD, professor and vice chairman of pediatrics; director, Program in Medical Ethics, University of Wisconsin School of Medicine.
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