Doctors in the UK have announced the birth of eight healthy babies through a pioneering IVF method that uses DNA from three individuals, reports the Guardian. The aim is to prevent the inheritance of incurable mitochondrial disorders. The approach, developed at Newcastle University, combines genetic material from the mother and father with healthy mitochondria from a donor, reducing the risk of passing on mutations, as described in a pair of papers in the New England Journal of Medicine.
The children—four boys and four girls, including identical twins—were born to seven women, all of whom were at high risk of transmitting mitochondrial diseases. None of the babies show signs of these disorders. Another pregnancy using the same technique is ongoing. Says the mom of one girl: "As parents, all we ever wanted was to give our child a healthy start in life. After years of uncertainty this treatment gave us hope—and then it gave us our baby ... we're overwhelmed with gratitude. Science gave us a chance."
Mitochondrial diseases are caused by mutations in the small amount of DNA housed in mitochondria, the cell's energy producers. Inheriting faulty mitochondria can lead to severe symptoms in childhood and, in the worst cases, early death. About 1 in 5,000 newborns are affected. The new treatment, called mitochondrial donation therapy (MDT), involves fertilizing the mother's egg with the father's sperm, then inserting the resulting nuclear DNA into a donor egg that has healthy mitochondria but no nucleus. This method, first licensed in the UK in 2017, provides children with genetic material from three people: nuclear DNA from both parents and mitochondrial DNA from the donor.
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While this instance is fairly limited in scope, its broader implications have clear detractors, notes NPR. "It's biologically dangerous," says Stuart Newman, a professor of cell biology and anatomy at the New York Medical College. "And then it's dangerous culturally because it's the beginning of biological manipulation that won't just end with preventing certain diseases, but will blossom into a full-fledged eugenics program where genes will be manipulated to make designer babies."