U.S. scientists recommend approval for three-parent embryo research

A panel of bioethicists and scientists in the U.S. gave cautionary approval this week to an ethically questionable process they say could prevent the transfer of congenital diseases from generation to generation. But it results in embryos with genetic material from three parents: a sperm, an egg, and a donor egg.

The National Academy of Sciences, Engineering, and Medicine assembled the 12-member panel to provide a report on the procedure for the Food and Drug Administration (FDA). The FDA requested the report last year after two groups of scientists in Oregon and New York requested permission to perform experiments.

In the procedure known as mitochondrial replacement technique (MRT), a scientist removes the nucleus from the egg with damaged mitochondrial DNA (mtDNA). The nucleus is then placed in an enucleated donor egg with undamaged mtDNA.

Mitochondrial DNA only contains 37 genes, a small number compared to the 20,000 genes contained in nuclear DNA. MtDNA is only transferred by the mother’s egg. And damaged mtDNA causes more than 200 incurable and fatal genetic disorders.

“This will be an amazing breakthrough, benefitting patients who otherwise could not have healthy, genetically related children,” Owen Davis, president of the American Society for Reproductive Medicine, told NBC News.

The panel released the 164-page report Wednesday, concluding experimentation on the procedure is “ethically permissible,” within certain guidelines.

First, researchers should conduct extensive preliminary research to determine safety. And the initial experimentation should be performed on animals and embryos that cannot develop. Second, the targeted disease should be severe. And finally, the procedure should only be performed on male embryos. A male embryo wouldn’t introduce unwanted genetic modifications into the gene pool since mtDNA is only transferred by egg.

“MRT, if effective, could satisfy the desire of women to have a genetically related child without incurring the risk of passing on mitochondrial disease,” the panel concluded.

But while researchers say the motive behind the MRT procedure is pure, critics advise extreme caution. The panel noted people with three genetic sources could struggle with their identity and ancestry. And scientists could use the procedure to genetically engineer humans. Marcy Darnovsky, executive director of the Center for Genetics and Society, said the panel’s conclusion that the research should continue contradicts the cautions raised.

“It’s important to realize that if the FDA were to approve these techniques, it would have few mechanisms for preventing what would essentially be ‘off label uses,’” Darnovsky said. “One U.S. proponent of these techniques has already made it publicly clear that he would like to expand their use widely to fertility clinics. Their use could easily spin out of control.”

Earlier this week, critics raised similar concerns about the British government’s approval for experiments on a technique known as CRISPR that allows scientists to alter nuclear DNA.

Darnovsky also told NPR the “three-parent” procedure could lead to a society where some people are genetically enhanced and others are “regular.”

“And I don’t think that’s a world we want to live in,” she said.

The current federal budget bans government funding to review applications for research “in which a human embryo is intentionally created or modified to include a heritable genetic modification,” the FDA noted in a statement issued Wednesday. Any U.S. research on MRT isn’t likely to happen in 2016.