A Colorado couple used genetic tests to create a test tube baby that would have the exact type of cells desperately needed to save their 6-year-old daughter, doctors said yesterday.
The case represents the first time a couple is known to have screened their embryos before implanting one in the mother's womb for the purpose of saving the life of a sibling.
The test tube baby, named Adam, was born in Denver on Aug. 29. Doctors collected cells from his umbilical cord, a painless procedure, and on Sept. 26 infused them into his sister Molly's circulatory system. The girl is recuperating in a Minneapolis hospital, and within about a week doctors should know whether the procedure was successful.
Whether or not the transplant works, doctors and ethicists said, the procedure is both a promising and worrisome harbinger of where scientific advances are taking human reproduction in the near future--at least for those who can afford to take that path.
On the one hand, experts said, that future will be one in which the power of genetics and embryo cell research will lead to novel therapies for incurable diseases. In this case the girl suffered from an inherited bone marrow deficiency that is universally fatal without a transplant like the one she got from her newborn brother.
"We knew we were running out of time," said Charles Strom, director of medical genetics at Illinois Masonic Medical Center, where the genetic testing was done. Now, he said, the girl has an 85 percent to 90 percent chance of being largely free of the marrow disease.
On the other hand, the new work also points to a future in which parents will have unprecedented options to choose the traits of their children, for whatever practical or capricious reason they may have.
"You could say it's quickly becoming like buying a new car, where you decide which package of accessories you want," said Jeffrey Kahn, director of the University of Minnesota's Center for Bioethics. "I suspect that it's only because we don't yet have the tests that we're not having parents asking for embryos without a predisposition to homosexuality or for kids who will grow to more than 6 feet tall."
The girl who received the cell transplant, Molly Nash of Englewood,
Colo., was born with Fanconi anemia, an inherited
disorder that causes a massive failure of bone marrow cell production.
Children with the disease suffer from anemia, bleeding disorders and severe
immune system problems and generally die from leukemia or other complications
by age 7. The only effective treatment is to get a batch of healthy cells
from a perfectly matched sibling to replace the ailing child's faulty bone
marrow cells.
Molly's parents, Lisa and Jack Nash, had long wanted additional children, but were afraid to conceive another for fear that it, too, would be affected by the disease. Each parent carries both a normal and a faulty version of the Fanconi gene, which meant they had a 25 percent chance of having an affected child with each pregnancy.
But a few years ago they learned of a new technique under development called preimplantation genetic diagnosis. Researchers harmlessly pluck a single cell from embryos that have been created by standard in vitro fertilization and are developing in a laboratory dish. They test each of those cells for the presence of a disease gene, and then transfer to a woman's uterus only those embryos whose cells test normal.
Lisa Nash said that when she tried in vitro fertilization for the first time a few years ago she turned to preimplantation genetic diagnosis primarily to select an embryo unaffected by Fanconi. She allowed researchers to test the embryos for compatibility with Molly's cells, but the tests were not very good then, she said.
The couple went through this four times, and each time benefited from increasingly sophisticated cell typing tests. But none of the attempts resulted in a pregnancy. Finally, in the fertility cycle initiated late last year, two of the couple's 15 embryos tested as both free of the disease and having a perfect match for Molly, Strom said.
Only one of those two embryos was healthy enough to transfer to Lisa's womb. On Christmas Eve the couple learned that the embryo had implanted properly and that Lisa was pregnant.
After Adam was born, doctors saved the blood cells from his umbilical cord. Research has shown that umbilical cord cells, like transplanted bone marrow cells, can travel to a recipient's bone marrow and repopulate the marrow space with healthy cells.
The transplant was performed last week at Fairview-University Hospital in Minneapolis, which specializes in bone marrow replacements for children with Fanconi anemia.
"Molly was holding Adam in her lap," Lisa Nash said, while the cells dripped through a plastic tube into the girl's chest. "It was the most awesome, monumental experience of our life, yet it was so simple. You'd think there'd be thunderbolts and lightning, but it was calm."
So far, doctors said, Molly is doing well.
"Molly's having no complications whatsoever. She's up and playing on the computer in her room," said University of Minnesota cord blood specialist John Wagner, who oversaw the transplant. Soon, he said, she will be out of the high-risk period that follows such procedures. Doctors suppressed her immune system with the radiation and chemotherapy to increase the chances the cells would not be rejected.
The Nash case is reminiscent of one in which a California man, Abe Ayala, had his vasectomy reversed in 1989, 17 years after the birth of his second and what he thought would be his last child. Ayala took the step so that he and his wife Mary could have a third child--one who might serve as a bone marrow donor for their ailing daughter Anissa.
At 16, Anissa had been diagnosed with a deadly form of leukemia, and the only possible cure was a cell transplant from a perfectly matched donor, none of which could be found. The Ayalas knew that they had one-in-four odds of having a child whose cells matched Anissa's and they took that chance. Luck was with them. Newborn sister Marissa inherited all the right genes from her parents, and the cells she provided saved her sister's life.
The new case differs in that luck was not a factor. That's a difference that some find reassuring, as it eliminates the chance a newborn will disappoint parents who had wished for a certain cell type. But some find that troublesome because it moves a step closer to "designer babies."
Both cases raise questions about whether there are "good" or "bad" reasons to have children--a concern that Strom was quick to dismiss.
"People have kids for all kinds of reasons: to save a failing marriage, to work on the family farm, to perpetuate the family name. In the scheme of things, this is the most wanted child I've ever met. They love the heck out of this kid."
© 2000 The Washington Post