-- Randy Dotinga
THURSDAY, Feb. 23 (HealthDay News) -- A second company reports
that it has developed a prenatal blood test to detect Down
syndrome, potentially providing yet another option for pregnant
women who want to know whether their unborn child has the
Last fall, Sequenom Inc. announced that it was making a prenatal
Down syndrome blood test, available in 20 cities in the United
States. It marked the first time that pregnant women could undergo
a Down syndrome test without having to go through amniocentesis or
chorionic villus sampling, which are invasive and pose a small risk
Now, two studies published online Feb. 21 and in the April print
issue of the
American Journal of Obstetrics and Gynecology suggest that
another blood test, this one developed by Aria Diagnostics, can
detect Down syndrome and a genetic disorder known as Edwards
syndrome, which can cause severe birth defects and is often fatal.
In both studies, testing was conducted before 20 weeks
One of the studies, written by Aria Diagnostics researchers,
correctly detected 44 cases of the two disorders out of 167
prenatal blood samples. The other study, by researchers from
University of London and University College London, correctly
detected all Down syndrome cases and 98 percent of Edwards syndrome
The test "would be useful as a secondary test contingent upon
the results of a more universally applicable primary method of
screening," senior study author Dr. Kypros H. Nicolaides, of the
University of London, said in a journal news release. "The extent
to which it could be applied as a universal screening tool depends
on whether the cost becomes comparable to that of current methods
of sonographic and biochemical testing."
Dr. Brian Skotko, a physician with the Down Syndrome Program at
Children's Hospital Boston, said the test's accuracy is "pretty
good," although the studies didn't test as many samples as Sequenom
did for its test.
Several other companies are developing prenatal tests for Down
syndrome, said Skotko, who predicted that competition in the
prenatal blood test market would lead to lower prices. Sequenom has
said that its test won't cost mothers more than $235 in
The growth of these kinds of tests raises major questions,
Skotko said: Will the tests become routine? If so, "will babies
with Down syndrome slowly start to disappear?"
Some pregnant mothers choose to abort their unborn children
after they are diagnosed with Down syndrome. Statistics suggest
that their numbers have risen in recent decades, Skotko said.
For more on Down Syndrome, go to
U.S. National Library of Medicine.
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