Three-parent Technique
The technique which Zhang used was spindle nuclear transfer, while the technique approved in UK is the pronuclear transfer. New Hope Fertility Center

Although it was the British Parliament which approved in February 2015 the in-vitro fertilisation (IVF) technique of three-parent IVF, it was a Jordanian infant who made world medical record as the first three-parent baby. The baby’s parents were treated in Mexico by a team of New York doctors.

The baby was formed using the father’s sperm, mother’s egg and an egg donor. The mother had a DNA which would have given her baby Leigh syndrome. Using the IVF technique, the team lead by Dr John founder of the New Hope Fertility Center in New York, removed some of the mother’s disease-causing mitochondrial DNA from an egg, and a healthy DNA from her was slipped into an egg fertilised by the father’s semen, reports News.com.au.

Dr John Zhang
Dr John Zhang, founder of the New Hope Fertility Center in New York. New Hope Fertility Center

Around one-fourth of the mitochondria of the mother, a 36-year-old woman, carry the disease-causing mutation although she is healthy. The genes of Leigh syndrome reside in the DNA in the mitochondria which provides energy for the cells and carry only 37 genes passed down to babies from the mother, explains New Scientist.

With the technique, the baby inherited DNA from the two parents and the egg donor. The DNA contribution from the egg donor, however, is very small.

If the DNA carrying the Leigh syndrome was not removed, the baby born would likely die a few years after birth because it is a severe neurological disorder. The two previous children of the mother died of the ailment at ages eight months and six years old.

The procedure was done in Mexico because the technique is not approved in the US. However, Zhang says, “To save lives is the ethical thing to do.”

The technique which Zhang used was spindle nuclear transfer, while the technique approved in UK is the pronuclear transfer that involves the fertilisation of both the mother’s and egg donor’s egg with the father’s semen. However, the UK technique is not appropriate for the couple who is Muslim and opposed to the destruction of two embryos that happens using pronuclear transfer wherein nucleus from the donor’s fertilised egg is discarded and replaced by the mother’s fertilised egg.

Zhang’s team used the spindle nuclear transfer approach to create five embryos of which only one developed normally. He will present the findings at the Scientific Congress of the American Society for Reproductive Medicine in Salt Lake City in October.

VIDEO: World’s first baby born with new “3 parent” technique

Source: New Scientist