A BREAKTHROUGH non-invasive prenatal test for Down Syndrome, developed by researchers in Cyprus, could be introduced into clinical practice within the next two years, it was announced yesterday.
“The new, non-invasive test provides considerable advantages as compared to the current invasive procedures and therefore it is expected to be introduced with high confidence as a routine test in the clinical practice in the near future,” said Dr. Philipos Patsalis, Chief Executive medical Director at the Cyprus Institute of Neurology and Genetics.
Down Syndrome or Trisomy 21, is the most common cause of mental retardation with an incidence of one in 600 births.
It is caused by the presence of an extra chromosome 21 – three instead of two — which leads to physical and intellectual impairment.
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.
Current procedures such as chorionic villus sampling or amniocentesis, involve the use of a needle which passes through the womb and collects placental cells or some of the fluid that bathes the foetus.
“Both procedures are associated with a considerable risk of foetal loss which is estimated to be 1.0 per cent of the pregnancies,” Patsalis told reporters yesterday.
Due to the risks, prenatal diagnosis of the syndrome is offered only to pregnant women who have a high risk of giving birth to a child with Down Syndrome.
Identified through the use of ultrasound and biochemical analysis, high-risk pregnancies make up between 8.0 to 10 per cent of total pregnancies.
“Following the genetic investigation of high-risk pregnancies, approximately 80 per cent of the Down Syndrome are diagnosed,” Patsalis said.
The new test carries no risks for the foetus, it can be offered to all pregnant women.
Patsalis said it is 100 per cent accurate and it does not require any specialised laboratory equipment or know-how.
A trial involving 80 pregnant women – at the 11th to 14th week of gestation — showed the test to have 100 per cent accuracy.
“All normal and all Down Syndrome cases were correctly identified providing 100 per cent specificity and 100 per cent sensitivity,” Patsalis said.
Patsalis and his team are now in the process of carrying out a larger-scale clinical study, essential to enable the introduction of the test into clinical practice.
“It is estimated that the new test will be introduced into clinical practice within the next two years,” Patsalis said.
The study will involve 1,000 pregnant women from around the world, who will undergo non-invasive and invasive tests simultaneously.
The team of researchers are also looking into modifying the new test so it can be used for non-invasive diagnosis of other syndromes like Patau and Edwards, which also cause various defects.
