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Image: picture-alliance/Bildagentur-online/AGF-Foto

World's first 'three-parent' baby born

September 27, 2016

The procedure was carried out in Mexico, outside of US regulatory frameworks. Doctors had used a new method combining DNA from three people to prevent the baby from inheriting a fatal disease.


Scientists confirmed on Tuesday that the world's first baby had been born using a controversial technique that combines the DNA from three different people in the embryo.

The baby boy was born in Mexico five months ago to Jordanian parents. He is reportedly healthy, according to an exclusive report in the New Scientist.

The United States has not yet approved the new method, known as mitochondrial transfer. Dr. John Zhang of the New Hope Fertility Center in New York City and his team performed the procedure in Mexico, where, he said, "there are no rules."

Many outside experts welcomed news of the birth. However, some voiced concern given that many aspects surrounding research behind the technique is still not fully understood. Others also criticized the team for performing the procedure outside of regulatory medical frameworks. 

Zhang told the New Scientist that saving lives was "the ethical thing to do," and that the baby was healthy and doing well.

Mitochondrial transfer

The mother of the child carried genes for the fatal nervous system disorder, Leigh Syndrome. She had passed on the disease to her two previous children, both of whom died at a young age. She also suffered four miscarriages.

To ensure that the genes for the disease in her mitochondria were not passed down, Zhang took her nuclear DNA and combined it with the mitochondria from an egg donor.

Künstliche Befruchtung
Image: picture alliance/dpa/R. Hirschberger

"He removed the nucleus from one of the mother's eggs and inserted it into a donor egg that had had its own nucleus removed," the New Scientist report said. "The resulting egg - with nuclear DNA from the mother and mitochondrial DNA from a donor - was then fertilized with the father's sperm."

Zhang and his team said they had tested the boy's mitochondria and found that less than one percent of the mitochondria carried the mutation for Leigh Syndrome.

"Hopefully, this is too low to cause any problems. Generally it is thought to take around 18 percent of mitochondria to be affected before problems start," the report said. 

Banned technique

The first instances of scientists attempting the "three-parent" technique began in the 1990s. However, some babies went on to develop mental disorders, leading to a ban on the technique. The problem is believed to have arisen due to the babies having mitochondria from two sources.

Zhang will present his method next month to the American Society for Reproductive Medicine in Salt Lake City, Utah.

Justin St. John, professor and Director of the Centre for Genetic Diseases at Monash University, said that he believed the "investigators should have submitted a manuscript for full peer review instead of announcing these outcomes in this manner."

David Clancy of Lancaster University said that pervious experiments on monkeys showed that maternal mitochondrial DNA could expand from low to significantly higher levels. 

"This would "allow disease to again be transmitted, so we must expect the possibility in humans," he said. "While we should remain vigilant about this technique as new information and research accumulates, let us hope this child grows up and has a long healthy life."

dm/kms (AFP, AP)

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