U.S. panel endorses technique to create "three-parent babies"

A U.S. panel of scientists and ethicists said Wednesday the U.S. government should approve clinical investigations of mitochondrial replacement, a technique that could prevent certain genetic diseases but would create babies with genetic materials from three parents.

The expert committee, which was convened at the request of the U.S. Food and Drug Administration (FDA), concluded in a report that it's "ethically permissible" to initiate clinical investigations of mitochondrial replacement therapy (MRT) in humans as long as "significant conditions and principles" are met.

Mitochondria are known as the powerhouse of cells and can only be passed on from the mother. Mutations in mitochondrial genes can lead to rare, serious diseases that are often fatal in childhood.

The use of MRT to prevent the transmission of such diseases, however, is controversial, as it involves substituting the faulty mitochondria in a mother's eggs with healthy mitochondria from another woman.

So far, Britain is the only country in the world to have authorized the so-called "three-person IVF (in-vitro fertilization)" technique.

But the FDA is considering whether to allow such a technique to be conducted in the United States, asking the Institute of Medicine (IOM) of the U.S. National Academies of Sciences, Engineering and Medicine to provide an ethical analysis report.

The final report from an IOM expert committee agreed to give a green light, but with some restrictions, which it said focused on protecting the health and well-being of children born as a result of the technique.

"In examining the ethical, social, and policy issues associated with mitochondrial replacement techniques, we concluded that the most germane issues could be avoided if the use of these techniques were restricted by certain conditions, rather than prohibiting them altogether," said Jeffrey Kahn, chair of the committee and professor of bioethics and public policy at the Johns Hopkins Berman Institute of Bioethics in Baltimore.

"Although MRT would not treat a person with a mitochondrial disease, its pursuit could satisfy prospective parents' desire to bear genetically related offspring with a significantly reduced risk of passing on mitochondrial disease."

One of those limitations laid out in the report is that initial MRT clinical investigations should be limited to women who are at risk of transmitting a severe mitochondrial genetic disease that could lead to a child's early death or substantial impairment.

Another is that in initial clinical investigations only male embryos created through MRT should be allowed to be placed in a woman for a possible pregnancy. That's because males can't pass on their mitochondria to their children.

"Following successful initial investigation of MRT in male embryos, FDA could consider extending MRT research to include the transfer of female embryos if clear evidence of safety and efficacy from male cohorts using identical MRT procedures is available, even if it takes a long period of time to collect this evidence," the committee report added.

The IOM committee recommendations were welcomed by U.S. scientists conducting such studies.

"I'm very happy that the expert committee reached this conclusion on the ethical permissibility of mitochondrial replacement techniques," said Eli Adashi, professor of medical science at the Brown University.

"The limitation of use of mitochondrial replacement to males was surprising and clever twist on their part that makes a lot of sense ... I would not expect it to get to the clinic in the near future, but we may see a clinical trial application soon and FDA will have to decide how to deal with it."

The FDA said in a statement Wednesday that it will carefully review IOM committee recommendations.

But It noted that the latest federal budget prohibits the agency from reviewing applications "in which a human embryo is intentionally created or modified to include a heritable genetic modification."

As a result, the FDA said, human subject research utilizing genetic modification of embryos for the prevention of transmission of mitochondrial disease cannot be performed in the United States at this time. Endit