FDA weighs risks of three-person embryo fertilization

Federal health regulators will consider this week whether to green light a controversial new fertilization technique that could eventually create babies from the DNA of three people, with the goal of preventing mothers from passing on debilitating genetic diseases to their children.

The Food and Drug Administration has framed its two-day meeting as a "scientific, technologic and clinical" discussion about how to test the technique in humans. But the technique itself raises a number of ethical questions, including whether the government should sanction the creation of genetically modified humans.

The FDA panel will hear from several prominent critics who oppose any human testing of the approach, arguing that it could be a slippery slope toward "designer babies," — in which parents customize traits like eye color, height and intelligence.

But the field's leading U.S. researcher will be on hand to explain and defend his work, which he describes as "gene correction," rather than "gene modification."

"We want to replace these mutated genes, which by nature have become pathogenic to humans," says Dr. Shoukhrat Mitalipov, who will present on Tuesday. "We're reversing them back to normal, so I don't understand why you would be opposing that."

The FDA meeting was prompted by Mitalipov's research at Oregon Health and Science University in Portland, Ore., where he and his staff have produced five healthy monkeys using the DNA-replacement technique. He is seeking FDA approval to begin testing in a handful of women who carry defective genes that can lead to devastating diseases in children, including blindness, organ failure and epilepsy.

An estimated 1 in 5,000 U.S. children inherit such conditions because of defective DNA in their mitochondria, small energy-producing organs found in the cell. Unlike most DNA — located in the nucleus of the cell — mitochondrial DNA is passed along only by the mother, not the father.

The experimental technique, if approved for use, would allow a woman to give birth to a baby who inherits her normal nucleus DNA but not her defective mitochondrial DNA.

To accomplish this, researchers would remove the nucleus DNA from a healthy female donor's eggs and replace it with the nucleus DNA of the prospective mother. After fertilization, the resulting child would inherit the mother's nucleus DNA — which contains most inherited traits like eye color and height — but the donor's healthy mitochondrial DNA.

The technique initially made headlines as a way to create babies with three parents, but scientists say that's an overstatement, since the child would have only trace bits of DNA from the donor.

No matter how it's described, the technique faces opposition from a broad spectrum of critics who say it presents serious medical, ethical and societal dilemmas.

Chief among these concerns is that the genetic changes created using the technique would be passed down to future generations, potentially spreading unintended health consequences throughout the population.

In a letter to the FDA, the Center for Genetics and Society points out that more than 40 countries — including Germany and France — have laws banning human gene modification that is passed on to future offspring.

The group's director says mitochondrial replacement would help only a tiny fraction of patients affected by such disorders, and they have other options like egg donation to create healthy children.

The Associated Press