OH BOY, OH BOY, OH BOY - world's first baby born with DNA from three people

Top News | Agence France-Presse and Carain Yeung 29 Sep 2016

The world's first baby has been born using a controversial new technique by US scientists to include DNA from three parents in the embryo.

The baby boy was born five months ago in Mexico to Jordanian parents, and is healthy and doing well, said the report in New Scientist magazine.

The boy's mother carried genes for a disorder known as Leigh Syndrome, a fatal nervous system disorder which she had passed on to her two previous children who both died of the disease.

She had also suffered four miscarriages.

The woman, whose identity was withheld, and her husband sought the help of John Zhang, a doctor from the New Hope Fertility Center in New York City, to have a baby that would be genetically related to them but would not carry the inherited disease.

The United States has not approved any three-parent method for fertility purposes, so Zhang went to Mexico where he was quoted by New Scientist as saying "there are no rules."

Since the mother carried the genes for the disease in her mitochondria DNA passed down from the maternal side, Zhang used her nuclear DNA and combined it with that from an egg donor in a technique known as spindle nuclear transfer.

"He removed the nucleus from one of the mother's eggs and inserted it into a donor egg that had had its own nucleus removed," said the report.

"The resulting egg - with nuclear DNA from the mother and mitochondrial DNA from a donor - was then fertilized with the father's sperm."

Zhang and his team are expected to describe their method at the American Society for Reproductive Medicine meeting in Salt Lake City, Utah, next month.

An abstract describing the research has been published in the journal Fertility and Sterility, but outside experts said much more remains to be understood about the research.

Attempts began in the 1990s to create a baby by injecting DNA from a donor into the mother's egg and adding sperm from her partner. "Some of the babies went on to develop genetic disorders, and the technique was banned," said the New Scientist report.

"The problem may have arisen from the babies having mitochondria from two sources."

Hong Kong gynecologist and obstetrician Kun Ka-yan said the baby's genes are more than 90 percent the same as his "real parents."

The baby's appearance and intelligence should reassemble his own parents as Kun said these factors are mainly determined by the nuclear genes.

He said only mitochondria genes have been passed to the baby from the donor, which in this case help to avoid inheriting Leigh syndrome.

This case is a breakthrough in gene therapy, Kun said, adding that the ultimate goal is also to eliminate other genetic disorders such as Down's syndrome.

"We all know that Down's syndrome is caused by an extra chromosome," Kun said.

"It will be great if we can just cut the problematic part of the nucleus out, but we cannot do it yet with current technology."

However, Kun said local laws governing birth science are stringent.

He could not say if such procedures could be conducted in Hong Kong as the technique involved ethical issues.

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