The Two-Way
10:27 am
Wed June 4, 2014

1 Baby, 3 Parents: Scientists Say Due Date Is In Two Years

Originally published on Wed June 4, 2014 1:17 pm

A new medical technique that could prevent mitochondrial disease would also create babies with three parents, a British health agency says. Officials say the time is coming for a technique that would use material from two women and one man to produce a healthy embryo.

"I think that [two years] is not a bad estimation," Robin Lovell-Badge of the Medical Research Council tells the BBC. "The other sorts of experiments that we thought were necessary, again it will take about two years to complete all of those."

The procedure targets problems in mitochondria, the energy-producing organelles that have their own DNA. Their genome is both prone to mutation and inherited maternally — characteristics that have led researchers to think up ways to help women who carry mutated genes to have healthy children.

The British panel has been reviewing two treatment methods that involve using either a donor embryo or a donor egg from a woman with normal mitochondria. The parents would contribute nuclear DNA, but the mitochondrial DNA would come from a donor.

Before that process occurs in Britain, it would have to be made legal. And as you might imagine, the review panel is also considering ethical and safety consequences.

"The direction of travel still suggests that it is all safe, but we don't know what's round the corner so we're being a little cautious," says Lovell-Badge, who is on a review board of Britain's Human Fertilization and Embryology Authority.

The HFEA group issued a report Tuesday saying evidence "does not suggest that these techniques are unsafe," but that more experiments need to be conducted before clinical treatments begin. (You can read the full report in a PDF).

The process under review is often called oocyte modification, or more generally, three-parent IVF. In the U.S., an FDA panel convened meetings about a similar procedure in February, seeking expert and public comment.

Those hearings sparked a conversation on WBUR's On Point, where Scientific American associate editor Dina Fine Maron said much of the talk about potential clinical trials revolved around the possible cascading effects of genetic tweaking.

One approach that was aired, Maron said, was "only selecting for male children through this method at first to limit the transmission of mitochondria, since indeed it comes from the maternal line."

Mitochondrial diseases have a wide range of symptoms that affect the brain, vision and hearing, as well as heart, kidney and muscle problems, according to the National Institutes of Health. They are both debilitating and incurable.

"Each year, 1,000 to 4,000 children in the United States are born with a mitochondrial disease," according to the United Mitochondrial Disease Foundation.

The organization says that due to misdiagnosis, the exact numbers aren't easy to pin down.

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