Simple blood test may diagnose Down syndrome before birth

From The Telegraph in the UK:

A cheap blood test that could allow doctors to check unborn children for Down's syndrome and other disorders has been developed by scientists.

Researchers hope it will provide a better alternative to invasive tests which give an accurate result, but raise the risk of the mother suffering a miscarriage.

They hope to have the test available within four years and have suggested it may eventually cost as little as £30 per patient.

The new test works by extracting the DNA of the foetus from the mother's blood and screening it for Down's syndrome and other abnormalities.

At present, pregnant women are given the odds on whether they are carrying a child with Down's syndrome, and if they want to know for certain they have to undergo one of two invasive processes; either amniocentesis or chorionic villus sampling. The first involves taking a sample of fluid from around the foetus and can, in some cases, cause a miscarriage even if the woman is carrying a healthy foetus. The second requires taking a fragment of the placenta.

The new test involves the same equipment needed for amniocentesis testing, but uses blood instead of amniotic fluid and is not invasive.

So far, researchers have been able to prove the technique works in principle and have described the results as “promising”. They hope to use the same method to detect other abnormalities in an unborn child’s DNA such as Edwards’ syndrome, which causes structural malformations in the foetus, and Patau’s syndrome, which can result in severe physical and mental impairment and is often fatal.

It could also be used to screen for muscular dystrophy and haemophilia.

Research on the new test began in 2009 and is ongoing. To date it has involved 21 women who have had pregnancy terminations or pre-natal diagnosis and screening procedures. Dr Suzanna Frints, of Maastricht University Medical Centre in the Netherlands, who carried out the research, said she hoped all women in the world would eventually be offered the test.

She said the next phase of development would need to involve more women to establish the accuracy of the test.

“Although we need to test and refine this technique further our results so far are promising,” she said.

“When we succeed in developing the procedure for use in maternal blood we will be able to offer a safe, cheap, fast, reliable and accurate non-invasive test, which will be of immediate benefit to pregnant women, young and old, all over the world.” Down’s syndrome is a genetic abnormality that affects around one in 1,000 babies born in the UK – about 750 babies a year – and is the most common cause of learning disability.

Prof Stephen Robson, spokesman for the Royal College of Obstetrics and Gynaecology, said there was an ''enormous research effort’’ going into finding the ''holy grail’’ of a non-invasive test for Down’s syndrome.

Ultrasound scans of the baby at 12 or 13 weeks and again at around 20 weeks will still be necessary to detect other abnormalities in the foetus as well as check age and growth.