Birth expected in mitochondrial donation for infertility trial

Greek and Spanish researchers have announced that a clinical trial using mitochondrial donation to treat infertility has resulted in a pregnancy.

Once born, the baby will be the first confirmed birth following maternal spindle transfer (MST) where this technique was not used to prevent transmission of mitochondrial disease. The researchers hope that it can offer an alternative to egg donation.

'For some patients, it's very hard to accept that they cannot get pregnant with their own [eggs],' said Dr Nuno Costa-Borges, scientific director of Spanish centre Embryotools. 'Spindle transfer may represent a new era in the IVF field, as it could give these patients chances of having a child genetically related to them.'

MST is not permitted in Spain, so Embryotools partnered with the Institute of Life in Athens, Greece, to carry out the clinical trial with approval from the Greek National Authority of Assisted Reproduction.

The pregnant woman is 32, Greek, and has previously had four failed IVF cycles and two surgeries for endometriosis. She is one of 25 women taking part in the study, but the researchers are waiting to see the outcome of the first pregnancy before doing more embryo transfers.

Mitochondrial donation was developed to prevent passing on potentially deadly mitochondrial diseases. Mitochondria are tiny organelles inside cells which have a small amount of their own DNA. Normally inherited only from the mother, if a woman's eggs contain mitochondria with a deleterious mutation, she could not previously have healthy, genetically related children. 

Mitochondrial donation allows the mother's nuclear DNA to be transferred into a healthy donor cell (whose nucleus is removed), so the resulting child had nuclear DNA from the parents and mitochondrial DNA from the donor. 

The first child resulting from MST was born in 2017 to an Israeli couple who had lost previous children to Leigh Syndrome. The treatment was extremely controversial, not least because the embryo transfer took place in Mexico, in a perceived attempt to sidestep regulations.

A clinic in Ukraine previously claimed to have established pregnancies using the related technique, pronuclear transfer (PNT) (see BioNews 885). The difference is that MST takes place before the egg is fertilised, and PNT just after.

MST and PNT are legal in the UK following a decision by parliament in 2015, but only when used to prevent passing on serious mitochondrial diseases. The first patients were approved for the treatment in February 2018 (see BioNews 936).