‘Three-parent babies’ born in UK after IVF advance

Scientists in Newcastle use donor DNA from a ‘second mother’ to prevent genetic damage being passed on

BRITAIN’S first “three-parent babies” have been born, after scientists in Newcastle used the donor DNA of the “second mother” to repair genetic damage.

The fertility technique allows doctors to replace an egg’s defective mitochondrial DNA with healthy DNA from a female donor to prevent children suffering from debilitating conditions such as muscular dystrophy.

The repaired eggs are then fertilised with sperm and the resulting embryos implanted in the birth mother, like traditional IVF, in a procedure called mitochondrial replacement therapy (MRT).

Although doctors have not announced the births, a freedom of information request to the Human Fertilisation and Embryology Authority (HFEA) by The Guardian newspaper confirmed that a “small number of babies” have been born using mitochondrial donation transfer.

It is not known whether the babies are healthy.

Commenting on the announcement, Prof Robin Lovell-badge, senior group leader at the Francis Crick Institute in London, said: “It will be interesting to know how well the technique worked at a practical level, whether the babies are free of mitochondrial disease, and whether there is any risk of them developing problems later in life. Or, if female, if their offspring are at risk of having the disease.

“Such problems might arise if there is ‘reversion’, where the initially small amounts of the mother’s mitochondrial DNA, with the disease-causing variant gene, that are carried over with her nuclear DNA, are amplified.

“The Newcastle team were aware of the fairly low chance of this happening before the clinical application of the techniques, but without MRT being used, the risks of the children having mitochondrial disease would be very high.”

The technique involves transplanting nuclear DNA – which has all the characteristics that make up a person – from a fertilised egg into a donated egg containing healthy mitochondria, or alternatively removing the damaged DNA from an egg and replacing it with healthy mitochondria.

Mitochondria act as the batteries of the cells to give energy, and if they do not work properly it prevents normal development. Scientists believe the technique could offer hope to about 150 women a year, with dozens already expressing an interest.

Although the process was pioneered at the Newcastle Fertility Centre, the first baby was born using the technique in Mexico in 2016. The UK did not approve the procedure until 2017.

Peter Thompson, chief executive of HFEA, said: “These are still early days for mitochondrial donation treatment, and the HFEA continues to review clinical and scientific developments. More information can be found on our website.”