Researchers have developed a new prenatal blood test that accurately detected Down syndrome and two other serious chromosomal defects in a small study of 18 pregnant women. The test scan fetal DNA present in the mother's blood to detect chromosomal anomalies, particularly with chromosomes 21, 18, and 13, which are associated with severe birth defects.

Employing a "shotgun sequencing" strategy using a high-throughput gene sequencing technology to identify millions of unique sequence "tags" in the fetal DNA, the scientists were able to correctly identify the 12 women who carried aneuploid fetuses and the six whose pregnancies were normal. Their results matched those of amniocentesis or CVS test that were done on the women.

The research group is now planning a larger scale study. The cost of the test is estimated to be about $300, with DNA sequencing accounting for the majority of the overall cost.

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