Embryos with two mums to remove the risk of hereditary diseases: new research

By Dr. Ananya Mandal, MDApr 16 2010

New research published in the journal Nature, could pave the way to world’s first genetically modified human baby. The research involves making embryos with genes from one man and two women. There are hundreds or families around the world who are left childless or have serious ill babies because they carry genes for hereditary illnesses. This research may bring hope to such couples. According to scientists on the team, within the next three years these women will be able to avail such techniques. There has been skepticism regarding ethical issues attached to making of “designer babies”.

This groundbreaking research is taken up at the Newcastle University. The team believes that there are hereditary disease carried by the mother’s eggs. These defective genes lie at the energy producing particles in the ovum called the mitochondria. Nearly 150 known diseases are linked to these mitochondria including liver failure, heart failure, strokes, blindness and deafness, epilepsy, muscle diseases, diabetes etc. According to this finding now these defective mitochondria can be replaced by good ones from another woman.

For the experiment they took up the natural mother’s fertilized eggs. The healthy part of the DNA that will determine how the couple’s baby will be like is removed. Another woman’s fertilized egg is taken and DNA from it is also removed creating a shell with good mitochondria. The DNA from the first woman’s fertilized egg is now placed in this shell creating a new fertilized egg with DNA from mother and father and mitochondria from donor mother.

Lead researcher, Prof Doug Turnbull believes, “A child born using this method would have correctly functioning mitochondria, but in every other respect would get all their genetic information from their father and mother…What we’ve done is like changing the battery on a laptop…The energy supply now works properly, but none of the information on the hard drive has been changed.” The team also said that the donor mother’s DNA formed only 0.2% of the baby’s DNA. The technique has been successfully tried on 80 eggs. Once these eggs were tested for another week for abnormalities they were donated to couples undergoing treatment for infertility. Professor Turbull also said that this “is a very exciting development with immense potential to help families at risk from mitochondrial diseases.” He added that, “We have no way of curing these diseases at the moment, but this technique could allow us to prevent the diseases occurring in the first place.”

But under the Human Fertilisation and Embryology Act 2009, it is currently illegal to create babies using embryos which have been manipulated in the laboratory. But Charities last night called on the Government to allow further tests before implementation of this technique. The Act however does have the provision to allow such a technique only if the Health Secretary provides a secondary legislation. There are lot of debates on playing with nature that have been raised before and there is a potential for serious ethical issue on this experiment too.

Quotes for & against

This study has been supported by Muscular Dystrophy Campaign, Wellcome Trust and Medical Research Council. Philip Butcher, chief executive of the Muscular Dystrophy Campaign, said: “These findings will be a ray of hope for people affected by mitochondrial diseases who can often be left with the heartbreaking decision of whether to have children who may be born with a serious illness…. We have an honest prospect of taking these diseases out at the knees….I would urge the (regulators) to permit fertility treatment using these techniques as soon as the method is proved to be effective and safe in humans.”

Sir Mark Walport, director of the Wellcome Trust also said, “This is exciting research that could lead to the major clinical advance of preventing devastating mitochondrial diseases by curing the disease in fertilised eggs.”

However skeptic believe differently. Josephine Quintavalle, from campaign group Comment on Reproductive Ethics, who oppose research on embryos, said: “In terms of experiments this is the worst that anyone has come up with…It is completely distorting the natural process. We have no clue what the long-term consequences will be.” The Department of Health also said via a spokesperson, “In addition to issues of safety and efficacy, there are serious ethical considerations to be taken into account….Any proposed regulations would be subject to significant public consultation and Parliamentary debate before they could become law.”