Sunday 4 December 2016

Three-parent babies on the way, say IVF experts

Jeremy Laurance

Published 20/04/2011 | 12:12

Leading scientists have appealed to Andrew Lansley to set a timetable for the introduction of a controversial technique known as "three-parent IVF" after a scientific review found no evidence it was unsafe.

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The procedure involves swapping genetic material before the IVF embryo is implanted in the womb to prevent the transmission of some of the most severe inherited disorders. But it would lead to permanent changes in the genetic make-up of children that would be passed on to subsequent generations and breaks new ground in IVF research.

Mitochondrial disease – mutations in small structures called mitochondria which surround the cell nucleus – is carried by thousands of women and is passed down the maternal line, leading to the birth of about 100 severely disabled children every year. Some women with the disorder have had up to six children who have died because of the severity of their disabilities.

In an open letter to the health secretary signed by the heads of the Academy of Medical Sciences, the Medical Research Council, the Wellcome Trust and four other bodies, the scientists said regulations governing use of the gene-switching technique should be drawn up now so it can be introduced without delay once sufficient evidence of its safety and efficacy has been amassed.

"Given the importance of such research for couples wishing to have children free of mitochondrial disease, and the speed at which research in the field is developing, researchers and patients now need assurance that such techniques will move into the clinic. We consider it essential that UK patients should benefit from treatments resulting from research conducted here," the scientists led by Professor Sir John Bell, president of the Academy of Medical Sciences, say.

Mr Lansley ordered a review of the science of the technique, carried out by a panel appointed by the Human Fertilisation and Embryology Authority (HFEA), which concluded that though there was nothing to suggest it was unsafe, further research was necessary.

The mitochondria are the power packs of the cell, contained in the cytoplasm that surrounds the nucleus, which provide it with energy. They carry very small amounts of genetic material, mutations in which lead to potentially fatal problems such as organ failure and symptoms including blindness.

Women may be carriers of the inherited disorder without being affected themselves and some, or all, of their children may be affected. To avoid it, the nucleus of the woman's egg or embryo, containing more than 99 per cent of her genes, is removed, leaving the affected mitochondria in the cytoplasm surrounding it behind, and placed in a donated egg or embryo with unaffected mitochondria, whose own nucleus has been removed.

The resulting child has more than 99pc of the genes belonging to its father and mother and less than 1pc from the donor.

The scientific review of the technique, co-chaired by Robin Lovell-Badge of the Medical Research Council, says further work is needed into the two methods of switching the nucleus – the maternal spindle transfer, conducted before fertilisation, and the pronuclear transfer, conducted after fertilisation – to check offspring born to rhesus monkeys are unaffected and that human eggs and embryos similarly treated grow normally in the laboratory.

Dr Lovell-Badge said: "Some people seem to be taking our report as negative and hesitant. It is not meant to be at all. We just need a little bit more information. In my view it won't take very long – a year and a few months. We don't know which of the two techniques is best."

Ethical and legal reviews still had to be conducted – one method involved the destruction of fertilised embryos – alongside the preparation of new regulations but these should happen in parallel with the extra scientific research so measures were in place to treat the first patients as soon as the technique was approved, he said.







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