New Tests for Down Syndrome, Preterm Labor : Experimental technologies diagnose Down syndrome and assess amniotic fluid to predict preterm delivery.


RENO, NEV. — New technologies that can screen through the entire metabolite or protein compliment of a fluid will soon produce both a test that can correctly identify the patient experiencing early contractions who will deliver prematurely, and a maternal blood test perhaps 100% accurate for Down syndrome, predicted two speakers at the annual meeting of the Society for Maternal-Fetal Medicine.

These tests could be ready for the clinic in a few years, the speakers said.

In much the same way that researchers can study genomics to identify all the genes in a particular cell, and RNA transcriptomics to identify specific genes being expressed in a cell, it is now possible to study proteomics and even metabolomics, to profile all the biochemical components of a given cell, organ system, or fluid in hopes of identifying specific biomarkers for a given condition.

Using that technology, investigators have now identified a profile of amniotic fluid that predicts which patients who go into premature labor with intact membranes will deliver early and therefore warrant tocolysis, said Roberto Romero, M.D., chief of the perinatology research branch of the National Institute of Child Health and Human Development.

Dr. Romero said he and his coworkers profiled 186 metabolites from the amniotic fluid taken from 115 women who were having premature contractions, and were able to find a group of carbohydrates that correctly identified those who actually delivered preterm with 88% accuracy. The women who delivered early had low concentrations of this group of carbohydrates, while those who did not deliver had high concentrations.

The profile correctly identified 39 of 40 patients who delivered at term, 29 of 33 patients who delivered early but had no evidence of intraamniotic inflammation, and all 42 of the patients who delivered early and had evidence of inflammation.

The individual carbohydrates in the group are not unique in any way, Dr. Romero said, and he speculated that they are fetal products.

Dr. Romero declared no personal financial conflict of interest with regard to the study, but the National Institutes of Health has applied for a patent based on the team's findings.

In another presentation, Mary D'Alton, M.D., said she and her colleagues took maternal serum from 50 Down syndrome-affected pregnancies and compared it with serum from 50 unaffected pregnancies, and have been able to identify a group of six proteins that when combined as biomarkers can pick up Down syndrome with 100% accuracy.

Two of these protein biomarkers are overexpressed in Down syndrome cases and four are underexpressed, and this pattern is present in both the first and second trimesters, said Dr. D'Alton, director of the division of maternal-fetal medicine at New York-Presbyterian Hospital, New York.

Most of these proteins have not previously been known to be associated with Down syndrome, and none of them are products of the expression of genes on chromosome 21, she added.

Dr. D'Alton's study was supported by the NIH and ProteoGenix Inc. of Portland, Ore.

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