PUBLISHED: 19:31 EST, 6 June 2012 | UPDATED: 04:08 EST, 7 June 2012
Thousands of genetic disorders in unborn babies could soon be identified without the need for risky and invasive tests – raising fears of an oncrease in the number of abortions.
Scientists have developed a revolutionary technique that maps the entire genetic code of a baby in the womb, using only blood and saliva samples taken from its parents.
But the method – which makes it possible to scan for some 3,500 disorders without physically disturbing either foetus or mother – will raise serious ethical questions.
Knowing from an early stage whether their child will have a serious condition, raises the possibility that mothers-to-be might opt to terminate the pregnancy.
Currently, most pre-natal genetic screening involves tapping fluid from the foetal sac, or taking samples from the placenta by either inserting a probe through the mother’s abdomen or the neck of her womb.
Such invasive methods can identify only a small number of birth defects including Down’s syndrome, spina bifida, cystic fibrosis and muscular dystrophy. They also pose risks for both mother and child.
The new research involved analysing DNA shed by the foetus and floating in the mother’s bloodstream.
Blood sample DNA from the mother was also studied as well as DNA extracted from the father’s saliva.
‘In future, a more refined and less costly version of the procedure could make pre-natal genetic testing far more comprehensive’
Fitting pieces of the genetic jigsaw together, US scientists at Washington University in Seattle were able to reconstruct the entire genetic code of an unborn baby boy.
The findings were checked by looking at the baby’s DNA after birth.
Parts of the baby’s genetic material inherited from each parent were predicted with more than 98 per cent accuracy.
Researchers were also able to identify 39 of 44 ‘de novo’ genetic mutations.
De novo mutations, which are not inherited, are thought to play a role in complex conditions such as autism and schizophrenia.
Lead scientist Dr Jay Shendure, who reported his findings in the journal Science Translational Medicine, said: ‘This work opens up the possibility that we will be able to scan the whole genome (genetic code) of the foetus for more than 3,000 single-gene disorders through a single, non-invasive test.’
In future, a more refined and less costly version of the procedure could make pre-natal genetic testing far more comprehensive, but experts believe a decade of further research is needed.