How far can science go in creating life?
A lot father than it used to, now that scientists enabled a couple that had lost two children to Leigh syndrome to have a baby boy by removing the nucleus from one of the mother’s eggs and placing it into a donor egg that had had its own nucleus removed.
John Zhang and his team at the New Hope Fertility Center in New York City helped a Jordanian couple that had experienced terrible trouble in conceiving. In 2005, the couple had a baby girl, who died at the age of six from a genetic mutation in the mother’s mitochondria that crippled the child with Leigh syndrome. The couple had another child who had the same problem, and died at the age of eight months.
New Scientist has revealed the details of the new procedure, which enable the couple to have a baby boy last April in Mexico, as the procedure is not permitted in the United States.
Because the couple is Muslim and objected to losing two embryos, the procedure approved in the UK, called pronuclear transfer, was eschewed. That procedure entails the mother’s egg and a donor egg being fertilized with the father’s sperm, then having their nuclei removed before they become early-stage embryos. The nucleus from the donor’s fertilized egg is replaced by the mother’s fertilized egg.
Instead, the scientists executed what they call spindle nuclear transfer, in which the nucleus from one of the mother’s eggs is removed and planted into a donor egg whose nucleus was taken out. The donor egg is then fertilized, which gives it the nuclear DNA from the mother and mitochondrial DNA from the donor. The scientists used a male embryo so the child that was to be born could not pass down inherited mitochondrial DNA
The new baby boy was tested and found to have less than 1 per cent of his mitochondria with the mutation; normally 18 per cent of mitochondria must contain the mutation for it becomes problematic.