A child was born using the revolutionary "three-parent" gene technique.
The five-month-old baby boy was born using a technique that incorporates DNA from three different people. The boy's parents were Jordanian and were treated by a team of medical experts in the U.S.
According to a report by New Scientist, the boy's mother carries genes for Leigh syndrome, a fatal disorder that affects the developing nervous system. The genes for the disease are found in DNA in the mitochondria, the "power packs" that provide energy to all living cells.
The three-parent gene treatment is designed to create human embryos that are free of the hereditary mitochondrial disease usually passed on by the mothers to their children. The defective mitochondria, which may cause degenerative disorders in children, are located in the body of the egg, separated from the rest of its DNA, which is stored in the nucleus.
The technique involves removing the nucleus of the mother's fertilized egg and transferring it into a nucleus-free egg from a donor with healthy mitochondria. The resulting embryo, which will have the mother's nuclear DNA and the donor's mitochondrial DNA, will be fertilized with the father's sperm.
The procedure, which is known as spindle nuclear transfer, was done by John Zhang and his team at the New Hope Fertility Center in New York City. Zhang used this approach to create five embryos, of which only one developed normally. This healthy embryo was implanted in the mother and the boy was born nine months after.
The method has been legally approved in the UK but not in the U.S., so Zhang went instead to Mexico to carry out the procedure. "To save lives is the ethical thing to do," Zhang said in a statement.
In 2010, researchers from the Wellcome Trust Center for Mitochondrial Disease at Newcastle University in UK demonstrated that the technique could work, although questions about whether or not it could produce healthy embryos were raised.
Zhang and his team tested the boy's mitochondria and found that less than 1 percent carry the mutation. Generally, it is thought to take 18 percent of mitochondria to be affected before health problems begin, New Scientists reports.
"This is a milestone technique," Zhang told Daily Mail Online. "It proves for the first time that genetic information from three people can avoid disease. We now know reconstitution of human eggs can produce a healthy baby.
Zhang and his team will detail their findings at the American Society for Reproductive Medicine's Scientific Congress in Salt Lake City in October.