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Hope for parents with mitochondrial diseases

11 February 2008
Appeared in BioNews 444

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 from different women it has been dubbed by the press as the creation of 'three-parent' embryos.

Mitochondria are tiny structures that provide cells with energy. Every cell in the body has between 1000 and 10,000 mitochondria. Whilst the vast majority of a cell's DNA is contained inside its nucleus, a handful of genes are found in the mitochondria - just 37 genes out of around 25,000 genes in total. Mutations in mitochondrial genes cause a range of disorders that affect one person in every 6,500 and include fatal liver failure, stroke-like episodes, blindness, deafness, diabetes and forms of epilepsy and muscular dystrophy. 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 mitochondrial genes from their mother.

The Newcastle researchers are working on a technique that takes the DNA from the nucleus of a newly-fertilised egg, and transplants it into an egg from another woman which has had all of its nuclear DNA removed. The resulting embryo would have mitochondria from one woman, but its remaining 25,000 or so genes would come from the mother and father who provided the fertilised egg. In this way, a mother could have a child without passing on her faulty mitochondrial genes.

The work is as yet unpublished, but at a recent scientific meeting of the researchers reported successful transplants in ten embryos, which were then grown in the laboratory for five days before they were destroyed. However, all these experiments were done by exchanging DNA between two 'failed' embryos left-over from IVF, which have abnormal amounts of nuclear DNA and so are inappropriate for implantation. It is not yet known if the technique will work with healthy embryos and eggs, although experiments in mice have been successful. Team leader Professor Patrick Chinnery said: 'there are still a number of scientific issues we've got to resolve, in terms of efficiency, and in terms of whether we can do this in eggs rather than in other embryos'.

A step towards three-parent babies?
Nature News |  6 February 2008
Q&A: three-parent embryos
The Daily Telegraph |  5 February 2008
Three-parent embryo formed in lab
BBC News Online |  5 February 2008
Transplant creates embryos with three parents
The Daily Telegraph |  5 February 2008
12 June 2012 - by Antony Starza-Allen 
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....
14 March 2011 - by MacKenna Roberts 
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.
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)...
15 November 2009 - by Dr Rebecca Robey 
A controversial new technique to improve the quality of eggs from older women undergoing IVF is being developed by Japanese scientists. Because the procedure involves using eggs from two women to create a single viable egg for fertilisation, it has sparked a media furore over the potential creation of what have been inaccurately dubbed 'three-parent embryos'....
1 September 2009 - by Adam Fletcher 
A variation of somatic cell nuclear transfer (SCNT), reported online in the journal Nature, could be used in humans to allow women with a certain group of incurable inherited conditions - known as mitochondrial disorders - to have children without passing on the condition. Because the technique, developed by Dr Shoukhrat Mitalipov and team from the Orgeon National Primate Research Centre, US, involves the the sperm from one monkey and two eggs from different monkeys...
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...
12 September 2005 - by Dr Virginia Bolton 
This week saw another very positive illustration of the rigour and effectiveness of the regulatory system that exists in the UK to licence research using human embryos. However, it also highlighted ambiguities in the wording of the 1990 Human Fertilisation and Embryology Act, which is currently the focus of a...
9 September 2005 - by BioNews 
The UK's Human Fertilisation and Embryology Authority (HFEA) has issued a licence to a team of scientists who want to carry out research on human embryos aimed at preventing genetic conditions caused by faults in the 'powerhouses' of the cell. Researchers at the University of Newcastle, funded by the Muscular...
21 October 2004 - by BioNews 
Scientists at the University of Newcastle are applying for a licence to create embryos with 'three parents', in order to prevent genetic conditions caused by faults in the 'powerhouses' of the cell. Doug Turnbull and Mary Herbert have submitted an application to the UK's Human Fertilisation and Embryology Authority, which...
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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