New Down’s Syndrome test gives hope but it’s still in the future

Poly — Sun, 13 Mar 2011 17:03:56 +0000

THE PROMISE of a new non-invasive, early-term test for Down’s Syndrome, announced by Cypriot doctors last week, could mean the end of a series of physically and psychologically traumatic experiences for many pregnant women.
Currently, the two existing tests for Down’s Syndrome are both invasive and both carry slight risks of spontaneous abortions. The most common is an amniocentesis which only takes place at about 16 weeks of pregnancy when a needle is inserted through the abdominal wall into the placenta. If Down’s is diagnosed and the mother chooses to terminate her foetus, it is already late into the pregnancy.
“This is very traumatic for the women involved. Women are haunted by their guilt. Their capacity to think collapses. They tell me: it is as though I was in a dream,” said psychotherapist Mando Meleagrou who runs a counselling service for women and couples dealing with birth complications at King’s College Hospital in London.
For some women, an abortion at that stage of the pregnancy – more than four months in – is simply not a choice.
“I could feel the baby kick; my baby grew,” said Sophia Nicolaou, a 50-year-old teacher. “I went in to have an amniocentesis knowing I would keep my son, no matter what the result was. I just wanted to be psychologically prepared.”
For women like Sophia, the announcement last week that a simpler, non-invasive blood test delivering a diagnosis as early as 11 weeks into a pregnancy has been developed by Philippos Patsalis and his team at the Cyprus Institute of Neurology and Genetics is excellent news.
“This new method is great for mothers,” said Sophia (not her real name). “The psychological factor is hugely important. It’s one thing to take a blood test and another to have to go through an invasive procedure. I couldn’t understand back then why I had to go through it.”
The test developed by Patsalis and his team over the past five years uses a small amount of blood from the pregnant woman to detect whether the foetus is at risk. He said that all normal and Down’s Syndrome cases were correctly identified in a trial involving 80 pregnant women.
But Meleagrou warns that the trauma for women might still be there, even when a less intrusive testing method is available.
“It’s the discovery that ‘there is something wrong with my baby’ which is traumatic,” she said. “And following that, it’s the decision to terminate the pregnancy which haunts women. All of them remember the anniversaries marking the diagnosis and the termination. All of them wonder.”
Cyprus is one of the few countries which does not have a purely age-related criterion for Down’s Syndrome testing. It used to be the case that women older than 35 years simply had to go through an amniocentesis and this still happens in many countries, including the USA.
“In many countries, women are often bullied into taking an invasive test because they’re older than 35,” said world renowned prenatal expert Professor Kypros Nicolaides of King’s College London. Nicolaides developed Chorionic Villus Sampling (CVS), the other existing test for Down’s Syndrome. Like amniocentesis it involves inserting a needle into the placenta but it can be carried out earlier, usually between 10 and 13 weeks of pregnancy. The downside, however, is that the risk of spontaneous abortion can be higher if the procedure is not carried out by properly trained doctors.
Currently in Cyprus, all women undergo routine initial screening – a blood test and an ultrasound test known as a nuchal fold scan. The results of these taken together with the age of the mother decides the level of risk of Down’s Syndrome and whether the mother should undergo either amniocentesis or CVS.
At 16 weeks of pregnancy, for 20-year-olds, one in about 2,000 foetuses has Down’s Syndrome.
At just 35 years, the risk is one in 300, which marks the transition from ‘low risk’ to ‘high risk’. The risk keeps escalating. At aged 50 a woman has a one in ten chance of carrying a foetus with Down’s Syndrome.
In Cyprus, about 1,000 women yearly take one of the two diagnostic tests and about ten of those will be carrying a foetus with Down’s Syndrome.
“Those who choose to keep the baby regardless, choose not to have the test. The overwhelming majority who take the test actually choose to terminate the pregnancy,” Patsalis said. From the women who do not take the test, three to five babies with Down’s Syndrome are born each year.
Though Patsalis’ research has been welcomed, it will take two more years to see whether the test can be introduced into clinical practice and the Patsalis’ trial sample is small, involving 80 pregnant women.
His team are planning a larger study, involving 1,000 women. The study is necessary to validate the team’s current results and to decide whether the new test can be introduced into clinical practice.
“It’s extremely unlikely that the test will remain 100 per cent accurate. It is very, very rare in the field of medicine for this to happen,” Nicolaides warned.
And even if the larger study does prove accurate, women may still choose the invasive tests for their breadth of coverage. Current tests not only are fully accurate but they also screen for every kind of chromosomal abnormality. Patsalis’ test screen could eventually be used to test for four other congenital disorders but it’s simply not as powerful yet.
For Nicolaides the great potential of Patsalis’ research if it does prove accurate in further tests is not just its non-invasive nature. “The new test eliminates the risk of [spontaneous] abortion, which is great for women,” said Nicolaides. “It’s great when we see initiative like this by Cypriots.”

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New Down’s Syndrome test gives hope but it’s still in the future