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HFEA asks scientists for advice on mitochondrial disease treatment

14 March 2011

By MacKenna Roberts

Appeared in BioNews 599

Health Secretary, Andrew Lansley has asked the Human Fertilisation and Embryology Authority (HFEA) to convene an expert group 'to assess the effectiveness and safety' of a fertility treatment that would enable children to be born without potentially devastating, incurable mitochondrial diseases.

The technique replaces defective mitochondria with donated healthy mitochondria via a reverse cytoplasm (which contains the mitochondria) transfer. The procedure to replace the defective mitochondria involves a transfer of the pro-nuclei DNA belonging to the prospective parents being transferred into the donor cytoplasm. The 'reverse' aspect is because it is easier to remove the compact nuclear DNA, the sperm and egg pro-nuclei, from the defective fertilised egg (the recipient) and transfer it into the healthy donor egg's cytoplasm than it would be to essentially suck out both cells' cytoplasm and transplant the donor egg's cytoplasm into the defective egg recipient.

All cells have numerous mitochondria in the cytoplasm which surrounds the nucleus. Mitochondria are small energy-synthesising structures vital to cell function, and are only inherited maternally from the egg's cytoplasm, meaning that mitochondrial defects will be inherited by all the offspring of an affected mother.

Mitochondrial disease is rare but can be devastating, including fatal liver, neurological and heart conditions, and affects 100 children annually in Britain.

The technique is controversial because mitochondria contain a tiny amount of DNA, roughly 35 genes, involved in healthy cell and organ function, but does not encode the information to define any human attributes.

Technically any child resulting from this therapy will have the genetic information from three people: nuclear DNA from both parents and mitochondrial DNA from the donor. The resulting child is therefore almost genetically identical to their parents, but absolutely identical in attributes. The only genetic difference accounts for healthy cell function. 

This genetic outcome has resulted in the media using the term 'three parent IVF'. Experts argue that the reference is a misnomer because mitochondrial DNA does not transfer any traits and therefore cannot amount to parentage any more than a liver transplant recipient would be considered to have four parents because the recipient contains the genetic DNA from four people.

Opponents fear that genetic manipulation of eggs and embryos, even in this most limited respect, may open the door to genetic engineering of babies.

The technique to transfer the parents egg and sperm pro-nuclei into a denucleated donor egg cell structure/cytoplasm is similar to the Dolly the sheep SCNT (cloning technique) but does not involve cloning. Reproductive cloning remains banned in the UK.

UK law permits the research but prohibits the clinical application of cytoplasm transplantation. When the law was updated in 2008 a provision was included to allow regulations to be introduced in the future to lift the prohibition for the prevention of mitochondrial disease.

Professor Alison Murdoch, director of reproduction at the University of Newcastle where licensed research is ongoing, says it is 'progressing very rapidly'. She estimates that the review process could take a year and should begin now.

The HFEA committee has called for evidence from experts to be submitted by 15 March 2011 for consideration on 25 March. The committee is expected to present its conclusions to the Government next month. If the Health Secretary decides to approve the procedure then the regulation will be put before Parliament for approval.

SOURCES & REFERENCES
BBC News | 11 March 2011
 
One baby, three parents, no disease
Times | 11 March 2011
 
Today program - BBC News | 11 March 2011
 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

12 June 2012 - by Antony Blackburn-Starza 
The Nuffield Council on Bioethics has published a review of the ethical issues raised by proposed IVF techniques, which aim to prevent the transmission of faulty mtDNA from mother to child. The report concludes the techniques are ethically permissible, provided further research establishes their safety....
13 February 2012 - by Dr Kristina Elvidge 
Mitochondrial diseases are soon to be brought to the attention of the general public, as the Government seeks to gauge the attitude of the nation towards a ground-breaking IVF treatment that could prevent these conditions being passed from mother to child...
06 June 2011 - by Dr Marianne Kennedy 
Women at risk of passing on mitochondrial disease to their children could use PGD to give birth to an unaffected child. The scientists at Maastricht University Medical Centre in the Netherlands claim their work has the potential to prevent the transmission of mitochondrial diseases...
03 May 2011 - by MacKenna Roberts 
Further research is needed into the safety and effectiveness of techniques to prevent children being born with mitochondrial disease, a Human Fertilisation and Embryology Authority (HFEA) report has concluded...

19 April 2010 - by Ruth Pidsley 
A team of researchers at Newcastle University in the UK has been successful in attempts to transfer genetic material from one newly fertilised human egg to another without carrying over the egg's mitochondria (the energy-producing structures of a cell)...
19 April 2010 - by Dr Kristina Mills and Dr Marita Pohlschmidt 
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15 February 2008 - by BioNews 
In last week's BioNews we published an article about research into possible new treatments for mitochondrial disorders, in which we stated that: 'Sperm do not contribute any mitochondria to the embryo (as they are all present within the tail, which falls off after fertilisation) and, consequently, children inherit all their...
11 February 2008 - by Dr Rebecca Robey 
Scientists at the University of Newcastle are developing a technique that they hope will enable women with a group of devastating hereditary illnesses - known as mitochondrial diseases - to have children without passing on their genetic disorders. Because the method involves sperm from one man and two eggs...
16 October 2003 - by BioNews 
Researchers from Sun Yat-Sen University in Guangzhou, China have succeeded in creating a pregnancy using an embryo containing the genetic material of three different people. An egg cell taken from one woman was fertilised by in vitro fertilisation (IVF), creating a one-cell embryo, or zygote. The nucleus of the zygote...

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