New Technique to Test Chromosomal Abnormality from Blood Sample

A new technique has been developed to test chromosomal abnormality from blood samples, doing away with the need for aminocentesis. Thus Down’ syndrome detection becomes that much easier.

Amniocentesis involves inserting a long needle through the mother's abdomen and drawing fluid from the womb.

Birth Defects - Genetic - Down Syndrome
Down’s syndrome, also referred by some, as ‘mongolism’ is a genetic condition that arises due to an extra copy of all or part of chromosome 21

The procedure carries a small risk of miscarriage or infection as well as being uncomfortable. Approximately one in 100 women who have the test will miscarry as a result, according to the Royal College of Obstetricians and Gynaecologists.

The new technique allowed scientists to pinpoint signs of chromosomal abnormality in a study of 18 pregnant women.

Down's syndrome occurs when a foetus has three copies of chromosome 21 instead of two. It can cause physical and intellectual impairments.

Amniocentesis
Amniocentesis is a procedure done after 15th week of pregnancy to obtain samples of the amniotic fluid to test for genetic disorders. A simple animation depicting the procedure.

If a foetus has three copies of chromosome 21 rather than the normal two, there will also be a relative increase in the quantity of chromosome 21 in the mother's blood.

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

About Genetic Testing
Genetic testing helps to confirm a genetic condition in an individual and involves q complex laboratory techniques

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

Carol Boys, chief executive of the Down's Syndrome Association, told BBC news: "There is no question that these non-invasive tests will be introduced in the next few years.

Down’s Syndrome Tests Hurting Unborn Babies
Charity Down Syndrome Education International has claimed that tests to check unborn babies for the presence of the syndrome were damaging too many babies.

"It's therefore incredibly important that potential parents are given accurate information on Down's syndrome before they make a choice about whether to terminate or not.

"We don't consider Down's syndrome a reason for termination but we recognise that bringing up a child with Down's syndrome isn't right for everyone."

The research is reported in the journal Proceedings of the National Academy of Sciences.

Source-AFP
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