Pre-pregnancy test used for selective egg implantation

? In what is believed to be a medical first, a woman with a gene that is all but certain to cause Alzheimer’s by her 40s gave birth to a baby free of the defect after having her eggs screened and selected in the laboratory.

Experts said it appears to be the first time preimplantation genetic diagnosis, or PGD, has been used for early onset Alzheimer’s. There is no similar test for the more typical form of Alzheimer’s, which strikes the elderly.

PGD, which can also involve the testing of early embryos, has been used to screen for other devastating diseases such as Tay-Sachs and sickle-cell anemia, which strike in early childhood. It is less commonly used to detect diseases that strike adults.

Medical ethicists say the latest milestone raises troubling issues, among them the rights of parents with disabling diseases to have children.

The patient, a 33-year-old married geneticist who had the procedure about two years ago, desperately wanted children, even though Alzheimer’s will probably steal her mind long before her daughter grows up.

“Today it’s early onset Alzheimer’s. Tomorrow it could easily be intelligence, or a good piano player or many other things we might be able to identify the genetic factors for,” said Jeffrey Kahn, director of the University of Minnesota’s Center for Bioethics. “The question is, whether we ought to.”

The patient, whose name was not released, has a brother and sister who developed Alzheimer’s in their 30s. Tests showed that she has a mutation called V717L that has been found to lead to the formation of the brain-clogging protein deposits that are a hallmark of Alzheimer’s.

The woman was well-informed of the ramifications, said her doctor, geneticist Yury Verlinsky. A PGD pioneer at Chicago’s Reproductive Genetics Institute, Verlinsky described his patient’s procedure at a news conference Tuesday. A report on the case appears in today’s Journal of the American Medical Assn.

The woman underwent in-vitro fertilization, in which eggs are fertilized in the lab and implanted in the womb. But first, the eggs were examined to find those that were free of the mutant gene.

Her daughter was born about a year ago. The woman is pregnant again after undergoing another round of testing.

Using PGD for early onset Alzheimer’s is “the only relief for at-risk couples,” Verlinsky said. He said he will not screen for gender or other “cosmetic” reasons, but otherwise does not pass judgment on which patients he will test.

“It’s not our place to make a moral decision for them,” he said.

PGD is not widely available, partly because the defects it tests for are generally rare. It is also tricky to perform. Verlinsky said PGD procedures, developed in the late 1980s, have resulted in about 700 babies worldwide. His clinic has done about 2,000 PGD procedures, resulting in over 200 babies.

PGD costs about $2,500 at Verlinsky’s clinic. His patient had to undergo two rounds of tests because eggs tested the first time both had the V717L flaw. The cost does not include the clinic’s $7,500 fee for in-vitro fertilization.

Testing for early onset Alzheimer’s falls within guidelines from the American Society of Reproductive Medicine, which sets standards for fertility clinics, said Andrea Bonnicksen, a member of the group’s ethics committee. The group supports PGD when used for medical reasons, though clinics can decide for themselves which conditions to test for, she said.