Abrahim Hassan (pictured) was created last year in Mexico from an egg containing DNA from his mother and father, and tiny amount of DNA from a third female donor. He is held by John Zhang, head of the New York City embryonic team who were ‘sailing very close to the wind’ according to a top UK expert
THREE-PARENT BABY TECHNIQUE
The first child to be conceived using the controversial technique was a boy born to Jordanian parents earlier this year.
The procedure was carried out at a clinic in Mexico.
By incorporating a small amount of donor DNA into his cells, the parents have avoided passing on a debilitating genetic condition to their son.
The genetic defect is carried in the energy-producing units inside cells, called mitochondria.
Unpublished test results of the boy, who is now eight months old, indicate he is healthy and has no sign of the genetic disease carried by his parents.
The levels of mutant mitochondria are low, around 3 or 4 per cent, with experts claiming the defective mitochondria will remain at acceptable levels.
The clinic where the boy was conceived is working with more couples hoping to avoid similar conditions.
Last year, reports suggest this ‘three-parent’ approach may have already been used by researchers in China, with a child born using the technique.
Another expert questioned the work was for being in effect ‘an experiment on a living child’ – potentially putting him at risk of genetic disorders from a technique that was not fully understood and should leave us ‘very concerned’.
Abrahim was conceived from an egg containing DNA from his mother and father, and tiny amount of DNA from a third female donor.
This extra DNA contained ‘mitochondria’ – the ‘power plant’ of the living cell.
The extra DNA was necessary to prevent the development of Leigh syndrome, a fatal nervous system disorder.
Top stem cell biologist Professor Robin Lovell-Badge, from the Francis Crick Institute in London, made his comments after details of the case appeared in the journal Reproductive BioMedicine Online.
Dr Lovell Badge said: ‘It is of, course, good news that the woman being treated was able to have an apparently healthy child with no signs of mitochondrial disease, but from the paper it seems that in many respects Zhang and colleagues were sailing very close to the wind and that luck played a large part in the outcome.’
He said the method used ‘gave a high frequency of abnormal embryos’ – with three out of four early stage embryos created having high levels of faulty DNA.
He added: ‘In the end they only had one normal-looking embryo that could be transferred into the patient.
‘They were lucky that this was indeed normal and that it gave rise to a pregnancy. And they were lucky that the proportion of abnormal mitochondrial DNA remained relatively low in most tissues.’
The technique is controversial because it involves altering inherited ‘germ line’ DNA that is passed to future generations.
Professor Lovell-Badge said the Mexican team used a method called electrofusion.
This uses an electrical charge to merge the donated mitochondrial DNA with that of nucleus.
IVF babies born after MRT would receive a tiny amount of DNA from a third person besides their mother and father – an egg donor
This method has been abandoned by other researchers including those in the UK because they gave a high frequency of abnormal embryos. Professor Lovell-Badge was not clear why the Mexican team used this method.
Critics have accused politicians and regulators in the UK of rushing to embrace a technology that is not proven to be safe and could pave the way to ‘designer’ babies.
Supporters say it offers new hope to thousands of families cursed by devastating inherited diseases. Around one in 4,000 adults in the UK is believed to suffer from a mitochondrial disorder.
The fertility clinic in Mexico which helped a couple to conceive the world’s first ‘three-parent baby’ says it plans to conceive a further 20 babies using the technique in the first half of 2017 (stock image)
Professor Lovell-Badge said his criticisms left aside ‘all the issues of consent and legality’.
The procedure was carried out in Mexico as the procedure would have been specifically illegal in the US, but was not covered by legislation in Mexico.
DNA in mitochondria play an important role in metabolism but do not affect appearance or personality.
WHY IS THE METHOD CONTROVERSIAL?
The therapy targets faulty mitochondria – the energy producing units found in cells and passed on by the mother – by replacing them with those of a healthy female donor.
Concerns have been raised about the technique as mitochondria contain a small amount of DNA, meaning the child inherits DNA from the mother, father and the donor.
It remains unclear if the procedure is safe and effective in the long term, or if children born using mitochondrial transfer will remain disease free as they mature.
Some trials have shown that faulty mitochondria persist, even after the procedure.
The UK’s fertility regulatory body has now approved the approach for use in the UK.
Creating a ‘three parent baby’ involves taking DNA from the nucleus of the mother’s egg.
This is done to leaves the ‘faulty’ mitochondrial DNA behind that is causing the genetic problem The DNA is injected into a donor egg which has its nucleus removed, but still contains ‘healthy’ mitochondrial DNA.
This hybrid egg is then fertilised by the father’s sperm and helped to develop into an embryo.
The final stages of the treatment, including implantation of the embryo into the womb, were carried out in Mexico to avoid breaching US federal law.
Mitochondrial Replacement Therapy (MRT) is officially sanctioned in the UK and a clinic in Newcastle has been given the go-ahead to select the first British patient for treatment, probably before the end of the year.
Professor Sir Doug Turnbull, director of the Wellcome Centre for Mitochondrial Research at the University of Newcastle, who has pioneered MRT techniques, said: ‘Mitochondrial donation is an important new IVF technique that provides more reproductive choice for women with mitochondrial DNA mutations.
‘In the UK there is a clear regulatory framework and Newcastle has recently obtained a licence from the HFEA to allow mitochondrial donation for women at risk of having severely affected offspring.
‘It is important that all reproductive options are explained to potential mothers and there is long-term follow-up of children born, all of which are planned in the UK.
This method has been abandoned by other researchers including those in the UK because they gave a high frequency of abnormal embryos. Professor Lovell-Badge was not clear why the Mexican team used this method
Dr David Clancy, from the University of Lancaster, said: ‘We now have data, albeit incomplete, on a person resulting from a mitochondrial replacement technique.
‘It might not be unreasonable to consider this as an experiment; an experiment which uses a child. A child who had no ability to consent …
‘Even a moment’s consideration of the ethical issues completely overridden by this work should make us very concerned.
‘Here in the UK I think it would be wise for the HFEA (Human Fertilisation and Embryology Authority), having granted a licence for this procedure, to clearly outline criteria for failure and for halting the programme.’