One Embryo from Three Parents

Feb. 5, 2008— -- British researchers today are reporting a potential new technique to spare thousands of children each year from a group of deadly inheritable diseases known collectively as mitochondrial disease.

These diseases might be prevented by altering human embryos, which are the product of two mothers and one father, the researchers said.

Isabelle Christenson, 9, has mitochondrial disease, which is passed from mother to child via the egg. Mitochondria -- the parts of cells that convert food into energy -- have their own DNA which is separate from that in a cell's nucleus. Isabelle has already suffered a stroke and undergone a kidney transplant, a stomach transplant and a liver transplant.

"Isabelle has about a year to live, the doctors told us about a week and a half ago, barring no more complications," her mother, Michelle Christenson, said.

Researchers can theoretically prevent the passing of mitochondrial disease in a child by extracting nuclear DNA from a mother with mitochondrial disease and a father, then injecting that DNA into a donor egg from a woman without mitochondrial disease.

The resulting embryo, in effect, had three parents but was disease-free. It inherited all the physical characteristics from Mom and Dad but received its healthy mitochondrial DNA from the woman providing the "donor egg."

Altering eggs is not a new idea but the groundbreaking development is the technique to actually prevent genetic disease. Researchers say the next step is to let these "three parent embryos" grow beyond a few days, to see if they can actually become healthy babies.

But for families like the Christensons, it's about preventing future generations from enduring this disease ever again.

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