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‘Genetic jigsaw’ baby raises embryo screening hope

Identifying normal embryos can add �3,000 to an IVF bill. Picture: Getty

Identifying normal embryos can add �3,000 to an IVF bill. Picture: Getty

  • by JOHN VON RADOWITZ
 

A BABY has been born with the help of a hi-tech genetic screening technique that raises the prospect of embryo selection on the NHS.

The American boy’s mother was one of two patients who were the first to try the “genetic jigsaw” method of identifying viable IVF embryos.

Another woman, also from the US, is said to be close to giving birth.

The technique, known as next-generation sequencing (NGS), uses computer software to match broken fragments of DNA.

It allows clinicians to spot chromosomal abnormalities in an IVF embryo very rapidly, without resorting to deep freeze storage while waiting for results, and can also be used to spot serious gene defects. Because of its speed and efficiency, NGS has the potential to slash the cost of embryo screening.

Identifying “normal” embryos that are likely to implant in the womb and produce a baby can add another £3,000 to the bill for IVF treatment, which is about £5,000 per cycle.

Dr Dagan Wells, from the National Institute for Health Research (NIHR) Biomedical Research Centre at Oxford University, who helped develop the new technique, said: “This is a very powerful method. We can look at all 24 different types of chromosomes and get a result in 24 hours, and do this at a cost a half to two-thirds of that of current screening techniques.

“I think we’re getting to the point where there would be a strong economic argument to offer this to the majority of IVF patients. At some point, we may cross a threshold where the economic argument makes the NHS look at this very seriously.”

Current guidelines recommend that women under 40 who cannot get pregnant should qualify for three cycles of free IVF treatment on the NHS.

The baby boy born in Pennsylvania a month ago is the first living “proof of concept” that NGS works.

IVF remains an inefficient process, with less than a third of embryos implanting in the womb and generating a pregnancy. When she is in her 30s, a quarter of a woman’s eggs are likely to contain genetic abnormalities. In her 40s, three-quarters of her eggs will be abnormal.

Aneuploidy, or having too many or too few chromosomes – the coiled “packages” of DNA found in the cell nucleus – is believed to be the main cause of the problem. For reasons that remain unexplained, chromosomal abnormalities are ten times more common in humans than in other species.

In the vast majority of cases, aneuploidy stops a pregnancy happening, or results in miscarriage. Sometimes, it can lead to congenital disorders such as Down’s syndrome.

Embryo screening involves separating out embryos with the best chance of producing a pregnancy from those with chromosomal abnormalities.

Traditionally it has involved a “beauty contest” in which technicians pick out the best-looking embryos for transfer to the womb. This technique is unreliable, since even an embryo that appears perfect under a ­microscope can harbour hidden chromosomal defects.

The NGS technique involves breaking up DNA into large numbers of fragments and then piecing together sequences that fit. If the number of “jigsaw” pieces turns out to be wrong, it indicates an abnormality.

 

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