Invasive testing for Down's syndrome could soon be obselete, thanks to a simple new blood test developed by scientists.

The scientists have used a new technique to identify a key DNA difference to correctly diagnose 14 Down's syndrome cases and 26 normal ones.

Dr Philippos Patsalis and his colleagues looked for chemical differences in the blood of the mother and child as it crossed the placenta. The researchers were able to identify the babies who had three copies of chromosome 21 (characteristic of a Down's child), rather than two.

Down's syndrome impairs a child's physical and intellectual abilities, although levels of severity vary.

Currently, around 30,000 women have no choice but to opt for one of two invasive tests if they want to establish whether they are carrying a baby with Down's.

Amniocentesis entails taking a sample of fluid from around the foetus and has a miscarriage rate of one in every hundred women tested. Chorionic villus sampling requires taking tissue from the placenta.

Dr Patsalis, of The Cyprus Institute of Neurology and Genetics, Nicosia, said: "The [new] method is simple and fast and easy to perform in every genetic diagnostic lab worldwide because it does not require expensive equipment, software or special infrastructure.

"The test is the first worldwide to demonstrate 100% sensitivity and 100% specificity in all normal and Down's syndrome pregnancies examined."

Posted by Penny Hosie on 8.3.11 Comment on this article by sending it to: penny.hosie@pavpub.com