The new tests take advantage of techniques that can isolate and analyze tiny bits of genetic information from the fetus that circulate in a woman’s bloodstream, in this case from cells or free-floating snippets of DNA or the related molecule RNA.
At least four companies are developing such tests, including Sequenom of San Diego, which plans to be the first on the market in June. The other companies hope to have their versions on the market within a year.
“For 50 years, folks have been working to develop a noninvasive genetic test for Down syndrome,” said Sequenom chief executive Harry Stylii. “People have described it as the Holy Grail of genetic testing. We are on the cusp of delivering that.”
At a meeting of the Society for Maternal-Fetal Medicine in San Diego last month, the company reported that results from 858 women showed that its test did not miss a single case of Down syndrome and produced only one false alarm, making it much more accurate than the currently available screening tests and on a par with amniocentesis.