New York, Sep 28 The world's first three-parent baby has been born in Mexico with the help a controversial new fertility technique that incorporates DNA from three people, and is reported to be healthy at five months of age.
The 'three-parent' technique allows parents with rare genetic mutations to have healthy babies. The boy's mother carries genes for Leigh syndrome, a fatal disorder that affects the brain, muscles and nerves of developing infants.
Genes for the disease reside in DNA in the mitochondria, which provide energy for our cells. The parents of the baby, a Jordanian couple, had been trying to start a family for almost 20 years.
Ten years after they married, the woman became pregnant, but it ended in the first of four miscarriages. In 2005, the couple gave birth to a baby girl.
Their daughter was born with Leigh syndrome, and died aged six.
The couple's second child had the same disorder, and lived for 8 months, the 'New Scientist' reported. The couple sought out the help of John Zhang and his team at the New Hope Fertility Centre in New York City.
Zhang used an approach called spindle nuclear transfer. He removed the nucleus from one of the mother's eggs and inserted it into a donor egg that had its own nucleus removed.
The resulting egg - with nuclear DNA from the mother and mitochondrial DNA from a donor - was then fertilised with the father's sperm.
Zhang's team used this approach to create five embryos, only one of which developed normally. This embryo was implanted in the mother and the child was born nine months later on April 6, this year.
When researchers tested the boy's mitochondria, they found that less than one per cent carry the mutation.
This may be too low to cause any problems; generally it is thought to take around 18 per cent of mitochondria to be affected before problems start, researchers said.
The team will describe the findings at the American Society for Reproductive Medicine's Scientific Congress in the US in October.