Newly proposed controversial IVF treatment, which avoids the risk of passing on inherited defects, could have health dangers, especially for males, according to a team of scientists led by the University of Sheffield.
Mitochondrial replacement therapy (MR) involves replacing the mother’s damaged mitochondria by that of a healthy donor. This would effectively create a baby with DNA from three parents but remove the mother’s mutated DNA to prevent the female from passing on these mutations.
The mitochondria supply cells with power but mutations in the mitochondria may result in inherited mitochondrial diseases which range from mild learning difficulties to debilitating conditions such as muscular dystrophy and other life-threatening heart, muscle and brain diseases. Each year one in 200 children in the UK are born with any such mutation and one in 4000 develops a mitochondrial disease.
MR is a controversial technique because it involves germ line modification of the embryo’s DNA. This means that the third party’s genetic material will not only be passed on to the child but also to future generations down the female line.
Earlier suggestions that replacing mitochondria is nothing more than replacing the batteries of a camera may well need to be reconsidered.
The research team led by Dr Klaus Reinhardt, from the University of Sheffield’s Department of Animal and Plant Sciences, in collaboration with Dr Ted Morrow from the University of Sussex and Dr Damian Dowling from Monash University in Australia, compiled evidence that indicates MR can profoundly change the expression of the normal DNA.
A donor’s mitochondria may therefore affect a range of important traits such as individual development, cognitive behaviour and key health parameters in the recipient.
“Many combinations of normal DNA and mitochondria don’t work so well together. For MR, we need to consider that every person is a different camera. Simply inserting new batteries can lead to complication, even if the donor is perfectly healthy”, said Dr Reinhardt.
“Complications occur more often in males because mitochondria are only passed down from mothers, never from fathers. Any negative effects of mitochondria on a male’s DNA can, therefore, never be removed by evolution.”
If detailed proposals regulating the MR procedure pass a public consultation and are approved by Parliament next year, the world’s first three-parent baby could be born in Britain by 2015.
Dr Reinhardt added: “This technology has the potential to allow affected mothers to have healthy babies. Continuing some of the promising research avenues may be an important step towards the safety of this technology.”