Maternal blood reveals foetal DNA

A Hong Kong scientist has discovered a
technique for analysing the entire DNA profile of an unborn child by testing
the mother’s blood. Dennis Lo, of the Chinese University of Hong Kong, says
that it will be possible to test for all kinds of diseases and disorders.

“Uncovering the foetal genome amongst
floating DNA is technologically akin to finding a needle in a haystack,” researchers
from his team told the London Telegraph. “The non-invasive nature of our
approach makes it safer than conventional procedures that require invasive
sampling. However the new approach also raises a number of ethical, legal and
social issues that require active discussion among clinicians, scientists,
ethicists and the community.”

Although media coverage focused on the exciting
possibility of tests which have no risk of miscarriage, the obvious question is
what should be done with the information. In many cases, parents will abort the
child. Ironically, the headline in one
newspaper was “DNA test to save the unborn”.

Dr David King, of Human Genetics Alert, a
UK lobby group, commented: “The danger of this new method is that it will
encourage parental choosiness about minor imperfections, or even cosmetic
features.”

Dr Lo and his team tested successfully for
beta-thalassemia, a genetic disease which causes anaemia. But they also hope
that the test can be used to detect Down syndrome, Edwards’ syndrome and Patau’s
syndrome, which can result in severe impairment. Eventually it could be
possible to screen for disorders like muscular dystrophy and haemophilia.

At the moment, application in a clinical
setting is remote because the results are complex and hard to interpret. “We’re
about a factor of 100 away from commercial capability, but that will
change,” Charles Cantor, one of the co-authors of the study and chief
scientific advisor at the genetic testing firm Sequenom, based in San Diego,
told Nature. ~ London
Telegraph, Dec 9

Michael Cook
genetics
prenatal testing

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Michael Cook

Michael Cook edits BioEdge, a bioethics newsletter, and MercatorNet, an on-line magazine whose focus is human dignity. He writes from Sydney, Australia.

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