Human Genetics Alert
Phone/Fax: 020 7502 7516
For immediate release March 18th 2012
HGA report shows that major safety issues in mitochondrial replacement techniques have not been addressed
A new report by Human Genetics Alert (1) shows that the HFEA has ignored important epigenetic risks to children in its analysis of the safety issues raised by ‘mitochondrial replacement' techniques (2). Our research shows that the mother's nuclear DNA, which is transferred to the embryo, is very likely to contain incorrect epigenetic markings that may cause disease. The highly invasive embryo manipulations are likely to cause further epigenetic risks. We argue that since there is already a safe and reliable method to prevent mitochondrial disease being transmitted to offspring, i.e. conventional egg donation, the HFEA should adopt a precautionary approach to the new techniques proposed by Newcastle researchers.
HGA Director Dr David King, said: “We are shocked that the HFEA has so far failed to properly assess the most important safety concerns raised by these techniques. Even the Newcastle researchers admit that epigenetic problems may be part of the symptoms of mitochondrial diseases. It is vital that scientists' enthusiasm does not override the welfare of the child.”
The major defect of the HFEA's 2011 report is that it virtually ignores the issue of epigenetics. Recent research has shown that the way in which cells control which genes are active, through epigenetic modification of DNA, is vital to the health of cells and organisms. So it is vital that any embryos produced by the mitochondrial replacement techniques (MST/PNT) are checked to make sure that they are normal in this respect. There are two ways in which embryos produced by MST/PNT might be effected (i) epigenetic effects caused by the manipulation of embryos, and (ii) epigenetic effects of abnormal mitochondria on the nucleus of oocytes.
A major concern is that eggs that contain abnormal mitochondria may also have epigenetic problems in their nucleus: using the mother's nucleus thus creates a risk to the child which would be avoided by using conventional egg donation. There is a great deal of evidence that mitochondria affect nuclear epigenetic markings and cell regulation in general. These changes can persist over long periods of time and appear to be central to diseases such as diabetes and cancer. Scientists from the Newcastle centre have themselves recently proposed that these effects may explain aspects of the pathologies involved in mitochondrial diseases (3). The nuclei of oocytes from mothers carrying mitochondrial mutations will have been exposed to such mitochondria during the period of egg maturation, which is a period of intense epigenetic activity. It is thus very possible that offspring produced using PNT or MST may suffer from some of the symptoms of the mitochondrial conditions that PNT and MST are designed to avoid. Until such a possibility is ruled out for each condition, a much safer and precautionary approach to preventing transmission of mitochondrial diseases would be to avoid the use of the maternal nucleus and to rely on conventional egg donation.
There is also abundant evidence that invasive assisted reproductive technologies such as the nuclear transfer involved in MST/PNT can cause epigenetic perturbations in embryos and offspring produced by them. Enucleation of eggs is traumatic, and has been compared to major transplant surgery, but its effects may in fact be even more severe because they could affect every single cell of the child. There is no body of data that would validate use of these techniques in a clinical setting.
HGA argues that the main benefit of the Newcastle techniques, that the mother is genetically related to her child can never justify the safety risks to the child and the social consequences of modifying the human germ line. But even if the HFEA takes a different view on this, the welfare of the child is the paramount consideration under the HFE Act. The existence of a safe and reliable technique ie egg donation means that there must be a precautionary approach to safety issues for the child. The report lists research that should be undertaken before approving MST/PNT.
Human Genetics Alert's report is attached. For more information contact Dr David King on 020 7502 7516 or 07854 256040.
Notes for editors
1. Human Genetics Alert is an independent secular watchdog group that supports abortions rights. The evidence in the report was compiled by Dr David King, a former molecular biologist (PhD, Edinburgh University).
2. In 2011 an HFEA panel of scientific experts produced a report on the safety of MST/PNT.
3. Chinnery, P. et al, 2012 International Journal of Epidemiology 41 177-187.