Wednesday, December 10, 2008

Karyomapping to screen "all genetic disorders" in IVF babies


British researchers have developed a revolutionary test that will let prospective parents screen embryos for almost any known genetic disease.

The £1500 (Rs 125,000) test, which should be available as early as next year, will allow couples at risk of passing on gene defects to conceive healthy children using IVF treatment, The Times reports.

Unlike current tests it takes just weeks from start to finish and is suitable for couples at risk of almost any condition.

At present only 2 per cent of the known genetic conditions can be identified by current tests.

The new test involves creating embryos by IVF and removing a single cell from each when they are two days old.

The cells are then tested using a technique known as karyomapping before a healthy embryo is implanted, The Times reports.

Developed at the Bridge Centre in London, the test can check for mutations that cause serious disorders such as cystic fibrosis, muscular dystrophy and Huntington's disease.

It can also screen for multiple genetic variations, so that scientists could screen for combinations that together confer higher risks of diabetes, heart disease or cancer.

Such applications would first have to be approved by the regulator.

The test will also reveal an embryo's future susceptibility to a host of medical conditions.

For example, parents could be told about their embryo's future risk of developing Alzheimer's disease, heart disease or breast cancer.

Professor Alan Handyside, who has pioneered the technique, will apply to the Human Fertilisation and Embryology Authority for a licence to use it.

"We are still validating it, but it is going to be a revolution if it works out," Handyside told The Times.

"It makes genetic screening very much more straightforward."

Technically, it would be possible to use the test to select an embryo with a particular eye colour or to screen for multiple genes known to affect height or weight.

But Alan Thornhill, the scientific director of the Bridge Centre, told The Times: "When you start looking for more than two or three traits, you've just got no chance of getting a match. You'd need thousands of embryos, and we don't have a practical way of making thousands of embryos."

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