New egg fusion technique

A team of French, Spanish and Italian researchers has developed a new technique that may one day allow some infertile women to have their own genetic child. The new method, reported by the scientists in this month's issue of Human Reproduction, involves replacing the genetic information of a donor egg with that of the patient's egg.

The technique could help those women whose embryos repeatedly fail to develop because of problems with the egg cell cytoplasm, which surrounds the nucleus. Although this problem affects less than ten per cent of women attending fertility clinics, they can currently only be treated using donated eggs. But by transferring the nucleus of one of her eggs to a donor egg with its nucleus removed, such a woman may be able to have a child who is almost entirely genetically her own (with the exception of the 37 genes present in the cytoplasm).

The team has successfully managed to transfer egg nuclei to donor eggs using two approaches. One method involves using a chemical 'glue' called phytohaemagglutin, and the other involves a delicate microscopic manipulation similar to that used for ICSI (intracytoplasmic sperm injection). 'Because ICSI will probably be the best way of fertilising the reconstructed eggs the mechanical method we've developed will have the advantage of simultaneously fusing the eggs and introducing the sperm in a single, relatively simple action' said Dr Jan Tesarik, head of the team.

So far, the scientists have not attempted to fertilise any of the reconstructed eggs, because the formation of embryos for research purposes is banned in France and Spain and strictly regulated in Italy. But Dr Tesarik believes they are now ready to try and develop treatment for women who might benefit from the technique.

A spokesman for the UK's Human Fertilisation and Embryology Authority said that any UK clinic wishing to offer the technique could apply for a licence to create embryos using the method, but that doctors would have to satisfy the authority that the technique was safe before a licence could be granted. A spokesman for the fertility group Issue said the technique may assist thousands of couples to have their own baby.