HEALTH

‘Three-Person Babies’ Get The Go-Ahead In The UK

New reproductive technologies could prevent certain deadly, inherited diseases

HEALTH
Illustration: Vocativ
Dec 05, 2016 at 4:04 PM ET

Update: On December 15th, as expected, the UK’s Human Fertilization and Embryology Authority (HFEA) issued their verdict on the technology, mitochondrial replacement therapy (MRT), that would allow three-person babies to become a reality in the country. Following the advice of the expert review panel they first convened five years ago, the HFEA announced it would let fertility clinics use the technique in select cases, namely with women who could pass on damaging mutations in their mitochondrial DNA to their children and who have no other options available to reduce that risk.

“Today’s historic decision means that parents at very high risk of having a child with a life-threatening mitochondrial disease may soon have the chance of a healthy, genetically related child. This is life-changing for those families,” said HFEA Chair Sally Cheshire in a statement.

Clinics will still have to jump through a few hurdles before they can offer MRT, though. They’ll have to apply for a license, passing safety and skill checks, then they’ll have to get a separate approval for each individual patient they’d like to treat. The move is the culmination of a process that first began in February 2015, when the UK Parliament passed regulations that allowed the use of MRT. Clinics, however, have been waiting for a formal stamp of approval.

Original article from December 6, 2016: 

It’s no Gattaca, but the United Kingdom is on the brink of becoming the first country to explicitly allow certain types of designer babies be born within its borders.

Last week, a review panel of experts brought together by the country’s Human Fertilization and Embryology Authority (HFEA) released a definitive report, calling for the embrace of reproductive techniques that would prevent select genetic diseases from being passed down from mother to child.

This is done by replacing the DNA in the egg cell’s mitochondria with another donor’s, which helps create what’s fashionably being called “three-person” babies. (In reality, only 37 out of our some 20,000 genes are spliced in.) Though the UK legalized the practice of replacing mitochondria in 2015, the HFEA’s stamp of approval is needed before fertility clinics can apply for a license to perform either of the two current leading techniques, maternal spindle transfer (MST) and pronuclear transfer (PNT). The panel recommended clinical trials of these procedures are “cautiously adopted” in cases where deadly diseases are likely to be inherited and there are no good alternatives.

Three-person babies actually aren’t a new thing. In the late 1990s, dozens of children were artificially conceived with a similar, if less refined, DNA replacement technique. By 2002, however, any human genetic editing was formally banned by the U.S. and informally discontinued elsewhere, following concerns the swap wasn’t foolproof enough and still led to children being born with their mom’s mutations or other complications. Since then, fertility researchers have been hard at work trying to perfect the original concept.

In September, Dr. John Zhang of the New Hope Fertility Center in New York City announced his team had helped a couple conceive the world’s first baby using MST. The relatively healthy mother had a mutation that could cause a rapidly fatal neurological condition called Leigh’s Syndrome in her children, and by the time she turned to Zhang, she already had lost two children to it. So far, her eight-month-old baby boy appears to be free of any disease.

Zhang had earlier failed to help a woman conceive healthy children using another procedure, PNT, which swaps out the nucleus from a donor fertilized egg with the nucleus of the mother’s fertilized egg and then implants it into her uterus. But the failure might have been related to her having triplets rather than the treatment’s failure itself. At this point, researchers are still not sure if one technique is better than the other.

His success aside, though, it seems doctors are close but still not quite there. A study published late last month in Nature recruited families with Leigh’s syndrome and used MST to create altered embryos. The technique, which instead replaces out the core nucleus from a donor’s egg cell with the mother’s before it’s fertilized by sperm, did create embryos with nearly zero mitochondrial DNA from the mom. In some cases, however, the developing embryos gradually lost the donor DNA and went on to have stem cells powered by their mom’s defective mitochondria. This loss may be less likely with more compatible donor DNA, the study authors suggested. Whether these results could or would translate to an actual pregnancy is still an unanswered question.

Referencing both Zhang’s unpublished findings and other research similar to the Nature study, the panel authors believe there’s enough evidence to move forward to larger human trials of the technology.

If nothing else, it’s hoped that legitimatizing the practice in the UK will help keep families from seeking it out in places with less stringent precautions or regulations. Zhang himself performed his procedure in Mexico due to legality issues in the U.S., a move that brought him plenty of criticism from fellow scientists. And in the wake of his announcement, other teams from China and the Ukraine have also reported using 3-person techniques in patients, perhaps signaling the start of a reproductive arms race.

In any case, it appears that as the UK goes, so too will the rest of the world. The HFEA will formally decide whether to move forward with clinical trials of the techniques by December 15th. From there, it may only be a matter of years before couples are able to use them.