New Down's Syndrome test developed

Updated 06.57 Tue Oct 07 2008

A non-invasive test for mothers-to-be worried that their unborn child has Down's syndrome has been developed.

The technique involves looking for tell-tale chromosome fragments in a blood sample.

"Non-invasive testing will be much safer than current approaches" - Professor Stephen Quake

At present a procedure called amniocentesis is used to test for chromosomal abnormalities but this involves inserting a long needle through the mother's abdomen and drawing off fluid from the womb.

As well as being uncomfortable and inconvenient, amniocentesis carries a small risk of miscarriage or infection.

Down's syndrome occurs when a foetus has three copies of chromosome 21 instead of two.

The problem is an example of aneuploidy, or having an abnormal number of chromosomes.

Professor Stephen Quake, from Stanford University, California, who led the new study, said: "Non-invasive testing will be much safer than current approaches.

"The earlier you know you've got a foetus with Down's syndrome, the better able you are to prepare."