Advertisement
YOU ARE HERE: LAT HomeCollections

Conceived to Save Ill Sister, Test Tube Baby Born Into Controversy

October 08, 2000|RICK WEISS | WASHINGTON POST

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 say.

The case represents the first time a couple is known to have screened embryos before implanting one in the mother's womb to save 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% to 90% 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 that child 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% 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 month 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.

Advertisement
Los Angeles Times Articles
|
|
|