Genetic testing crosses brave new threshold
Cells are taking over functions of bone marrow
Transplant surgeons declared a success in the first-ever transplant of umbilical cord blood from a genetically screened and selected embryo that gained national media attention.
Tests showed the transplant is working, says John Wagner, MD, principal investigator of umbilical cord blood transplant studies at Fairview University Medical Center, where the transplant occurred. Fairview is part of the University of Minnesota in Minneapolis.
Umbilical cord blood was transplanted from Adam Nash to his 6-year-old sister, Molly, who suffers from a debilitating genetic disorder called Fanconi’s anemia. "The infused cells are taking over the functions of Molly’s bone marrow, making platelets and disease-fighting white blood cells. The bone marrow graft is recovering extremely well," adds Wagner.
Research promises hope
Wagner’s research at the University of Minnesota School of Medicine focuses on five areas:
1. Increasing the number of stem cells collected from a donor by nourishing them under laboratory conditions so they naturally make more stem cells. Then larger and stronger doses of stem cells will be available.
2. Understanding the mechanism of graft vs. host disease, a major complication of both bone marrow and cord blood transplants. If this condition can be prevented, success rates of transplants of all kinds will greatly improve.
3. Genetically marking stem cells so that researchers can follow them in the body and, in that way, understand how they function.
4. Evaluating the success of transplants done with unrelated donors.
5. Treating Fanconi’s anemia with marrow and cord blood transplants.
Adam was born through in vitro fertilization this past summer. His parents genetically screened and selected an embryo to make sure it would be free of Molly’s disease and would be a tissue donor match. "What’s significant is that this is the first time preimplantation genetic diagnosis [PGD] has been used for the expressed purpose of insuring a perfect stem cell donor for the treatment of a sibling with Fanconi’s anemia," notes Wagner.
Questions for society
The use of these techniques raises important ethical issues for families and society, however, says Jeffrey Kahn, PhD, director of the University of Minnesota’s Center for Bioethics in Minneapolis. Questions raised by the transplant will have far-reaching implications, he notes.
Could this scenario be an example of the genetic revolution going too far? Or is it just an example of using modern medicine to benefit everyone involved, Kahn questions.
Making sure that an embryo would be a matched donor required two kinds of genetic tests. First, the embryos were tested for Fanconi’s anemia, with only the unaffected embryos being tested a second time. The second test determined which embryos were genetically compatible with Molly.
Process isn’t new
The PGD technology is about five years old, notes Kahn, but until now has been used to help would-be parents avoid passing on genetic diseases or illnesses to their children. But this case raises new ethical issues because PGD was used for a different purpose, he says.
Because the technology was used based on the interests of somebody else — a sibling, parent, or someone else — rather than in the interest of protecting the health of the unborn child creates a moral dilemma, Kahn notes.
For Adam, there was no beneficial or harmful impact on his health by participating in the procedure. But, Kahn questions, what about future cases where parents may want to use the technology for more controversial characteristics, such as musical ability, height, or others?
The only way to prevent PGD from being used in an unacceptable manner is the creation of rules to determine what traits can be chosen, suggests Kahn. Another option would be to review each couple’s request for the use of PGD.
Kahn also notes that, regardless of motive, many more parents will follow in the footsteps of the Nashes. The costs of PGD will be high, both in terms of money and morals, he notes. Perhaps the biggest question is whether society is willing to pay those costs.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content