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expert reaction to reports of the first baby born (in Mexico) using the mitochondrial donation technique

A paper outline published online in the journal Fertility and Sterility and to be presented at the American Society for Reproductive Medicine conference in October reported what is thought to be the first baby born using mitochondrial donation techniques for the purpose of disease prevention.

All our previous output on this subject can be seen here.


Prof. Doug Turnbull, Professor of Neurology, Newcastle University, said:

“Mitochondrial donation is a technique that offers hope to mothers who carry mitochondrial DNA mutations. There have been extensive discussions in the UK to ensure that families with mitochondrial disease get the best possible advice about their reproductive options and that any new IVF based technique is appropriately regulated and funded. This abstract gives very little information about the technique used, the follow up of the child or the ethical approval process.”


Prof. Justin St John, Professor and Director of the Centre for Genetic Diseases, Monash University, said:

“It is very hard to comment as this is just a meeting abstract where all the important relevant information is not available.

“As this technology is controversial and a world first, I think the investigators should have submitted a manuscript for full peer review instead of announcing these outcomes in this manner. The review process would have ensured complete validation of the data and provided a tested platform from which to conduct a debate about the degree of achievement. As it now stands, there will be much conjecture. For example, there will be much discussion about whether sufficient tissues in the offspring were analyzed to draw reasonable conclusions about the low level of mtDNA mutation transmitted.

“Furthermore, as part of the peer review process, the genetic testing results would have undergone rigorous assessment and further analysis could have been requested to ensure no doubt existed. Until we know these outcomes, it is very difficult to comment.

“Nevertheless, if all the validations are sound, this represents a first for the treatment of some very serious disorders. However, extensive monitoring will be required as there has been limited testing of this technology in appropriate animal models.”


Dr David J Clancy, Lecturer, Lancaster University, said:

“It is quite confronting to have the actual procedure reported for the first time in a human. It throws the range of ethical and practical issues into immediate and sharp relief.

“With MRT, the choice is between IVF by donor embryo vs. MRT to allow the mother to have a genetically related child. That is the benefit the procedure provides. In this case the procedure itself sounds little different to what would likely happen in the UK, except possibly the patient might have been offered IVF by donor embryo earlier, so might not have had the affected children who subsequently died. But we do not know the order in which her pregnancies and live births occurred, we do not know how the patient was recruited and we do not know the importance she attached to bearing a child who is related to her genetically.

“From the brief report it is not clear what the levels of disease mtDNA are in the various tissues of the offspring, although the average is relatively low, nor is it clear whether the +/-0.92% is standard deviation, standard error or a confidence interval, although we assume standard deviation. This is important because we know that the procedure is not perfect, generally transmitting disease mtDNA at low levels as is the case here, and we now know that tissue-specific expansion of mutated mtDNA during development can occur (Naue, 2015) and so could cause disease if levels are high enough. Also, in MRT experiments in macaque monkeys, expansion of original maternal mtDNA from low levels in embryos to significantly higher levels in eggs has been documented, which would allow disease to again be transmitted, so we must expect the possibility in humans.

“It is therefore perhaps good that the baby is a boy, as was recommended by the US panel who considered but recommended against MRT, since a female child with the mutant mtDNA levels reported in this male baby could transmit the mutation upon becoming pregnant herself.

“While we should remain vigilant about this technique as new information and research accumulates, let us hope this child grows up and has a long healthy life.”


Prof Simon Fishel, Founder and President, CARE Fertility Group, and Professor of Human Reproduction, said:

“This is a devastating disease that we do not wish children to be born with, and what’s more, we would wish to eradicate from any family lineage – and this technology will help achieve this. However, any first-time medical procedure moving from successful animal studies to the human, that will take several years until we understand its impact, is a necessary experimental step forward, which we hope and believe should be totally safe and utterly effective. Congratulations to this team and all those hoping to help these unfortunate families; and we should proceed with caution and due regulation.”


Sarah Norcross, Director of the Progress Educational Trust, said:

“The good news is that it seems a healthy baby has been born and this therefore should be a positive addition to the evidence the regulator’s scientific advisory panel is currently reviewing before a UK clinic can apply for a licence.

“In Mexico there are neither laws nor regulations relating to mitochondrial donation so while it is not illegal, the use of this technique has not been approved by their government. The situation could not be more different in the UK, where the government has been proactive in changing the law to permit the use of mitochondrial donation and a regulatory framework is in place to keep the procedures under close scrutiny.”


Prof. Bert Smeets, Professor Clinical Genomics, Director Genome Center, Maastricht University, said:

“At last, the first child of a mother with a mtDNA mutation is born after mitochondrial donation. The safety of the method had already been quite convincingly demonstrated by the Newcastle group in the UK and introduction into the clinic would only be a matter of time. Obviously, dependent on national regulation or the absence of it.

“A US-based research group apparently escaped the more rigid regulatory framework in the US to perform this treatment in Mexico. That is a concern, especially as the framework not only safeguards the introduction into the clinic, but also the follow-up of the children born after this treatment. To find out if the treatment is completely safe might take years and requires a centralized and standardized follow-up. It is striking that the Mexican ethical board approved this case, as the mutation load in the mother and the type of mutation would make it perfectly suited for preimplantation genetic diagnosis, which is a safe and accepted treatment. Hopefully, now the first child is born and the heat is off, it takes away the pressure to involve patients in unsecured treatments, when good alternatives are available.”


Dr Dusko Ilic, Reader in Stem Cell Science, King’s College London, said:

“Without much ado it appears the first mitochondrial donation baby was born three months ago. This was an ice-breaker. The baby is reportedly healthy; hopefully, this will tame the more zealous critics, accelerate the field, and we will witness soon a birth of the first mitochondrial donation baby in the UK.

“But some questions remain. By performing the treatment in Mexico, the team were not subject to the same stringent regulation as some other countries would insist on. We have no way of knowing how skilful or prepared they were, and this may have been a risky thing to do. On the other hand, we have what appears to be a healthy baby. Because it was successful, fewer questions will be raised but it is important that we still ask them.

“Was this the first time ever they performed the technique or there were other attempts and they are reporting this one because it was successful? This and other important questions remain unanswered because this work has not been published and the rest of the scientific community has been unable to examine it in detail. It’s vital that that happens soon.

“So it appears to be a good end result. But it risks encouraging others to follow the example, as we saw with ‘stem cell tourism’. That could be dangerous as understandably impatient people pursue treatment in the very places where regulation is the least strict.”


James Lawford Davies, Partner, Hempsons, said:

“The UK has a robust regulatory framework which ensures that centres seeking to offer such treatments are suitably skilled and equipped, that the use of the treatment has been subject to ethical scrutiny, and that all patients have provided their fully informed consent. No such statutory framework exists in Mexico, which means that it falls to those involved to self-regulate.”


Prof. Alison Murdoch, Head of Newcastle Fertility Centre at Life, Newcastle University, said:

“If this baby has been born as suggested then that would be great news. The translation of mitochondrial donation to a clinical procedure is not a race but a goal to be achieved with caution to ensure both safety and reproducibility.”


Prof. Darren Griffin, Professor of Genetics, University of Kent, said:

“This study heralds a new era in preimplantation genetics and represents a novel means for the treatment of families at risk of transmitting genetic disease. With radical new treatments like this there are always challenging ethical issues however any concerns need to be balanced against the ramifications of not implementing such a technology when families are in need of it. The Reprogenetics group are among the world’s leading.  One case is of course only proof of principle at this stage however I can see more treatment cycles being performed both sides of the Atlantic in the near future. The diseases to which this treatment is relevant are devastating and thus this treatment brings new hope to many families.”


Prof. Mary Herbert, Professor of Reproductive Biology, Newcastle University, said:

“It is difficult to comment on a study that has not been through the peer-review process.”


Dr Beth Thompson, Senior Policy Adviser at the Wellcome Trust, said:

“It is important to note that mitochondrial donation is tightly regulated in the UK, and any clinic wishing to offer such procedures would first have to apply to the Human Fertilisation and Embryology Authority for a licence. This robust system was established by an overwhelming parliamentary vote in 2015, which followed a decade of reviewing scientific, ethical and public opinion.

“The HFEA’s expert panel are currently reviewing whether the evidence supports the HFEA issuing licences in the UK.”


Outline title: ‘First live birth using human oocytes reconstituted by spindle nuclear transfer for mitochondrial DNA mutation causing Leigh syndrome’ by J. Zhang et al. published in outline form by the American Society of Reproductive Medicine’s Fertility and Sterility journal website.


New Scientist article.


Declared interests

Prof. Doug Turnbull: Prof Doug Turnbull receives funding from the Wellcome Trust for research into mitochondrial donation techniques and other research into mitochondrial disease. His other research is supported by MRC, BBSRC and NHIR.

Dr David J Clancy: “No interests declared.”

Prof. Simon Fishel: “For the avoidance of doubt CARE Fertility does not undertake this work, and has no plans to do so. Thus I have not conflict on that front.”

Sarah Norcross: “None.”

Dr Dusko Ilic: “No interests to declare.”

Prof. Alison Murdoch declares that she has no relevant interests.

Prof. Darren Griffin: “Treasurer of the Preimplantation Genetic Diagnosis International Society (PGDIS); Faculty of COGEN (Controversies in Genetics); President of the International Chromosome and Genome Society; Director of the Centre for Interdisciplinary Studies of Reproduction (CISoR)”

Prof. Mary Herbert: Mary Herbert’s research into mitochondrial replacement techniques is funded by the Wellcome Trust, the Barbour Foundation and the NIHR Newcastle Biomedical Research Centre. Other research in her lab is funded by the MRC and by the European Commission.

No others received.

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