A baby boy was born to a Jordanian couple who underwent mitochondrial transfer therapy performed by a New York-based team to prevent passing on a fatal mitochondrial disease to him, New Scientist reports. The baby, who was born five months ago, appears to be doing well so far, it adds.
"This is great news and a huge deal," King's College London's Dusko Ilic tells New Scientist. "It's revolutionary."
The technique involves using nuclear DNA from two parents and mitochondrial DNA from a donor and has been hailed as a way to avoid passing on mitochondrial diseases, but some critics say safety studies are needed to assess long-term effects. The method hasn't been approved in the US — this treatment was performed in Mexico, New Scientist notes — and some like Richard Paulson, the president-elect of the American Society for Reproductive Medicine, argue that the ban "is not scientific, not rational, not evidence-based," as he tells the New York Times. The approach was approved in the UK last year.
In this case, the mother is a Leigh syndrome carrier — about a quarter of her mitochondria harbor disease-causing mutations — and she'd passed the fatal neurological disease on to two previous children, who died at age six years and eight months, respectively.
John Zhang at the New Hope Fertility Center in New York took a spindle nuclear transfer approach to treat the couple: a nucleus from the mother's egg was transferred into a nucleus-less donor egg and then fertilized with the father's sperm. Using this approach, he created five embryos, one of which developed normally and was implanted into the mother.
Imperial College London's Sian Harding tells New Scientist that Zhang and his team appear to have taken an ethical approach as they avoided destroying embryos and used a male embryo that won't then pass on any inherited mitochondria.
However, the University of California, Davis' Paul Knoepfler tells NPR that this work is "troubling."
"It could have gone wrong in any number of ways and still could," he adds.