Pregnancy ultrasound 23 weeksStephen Quake is at it again. In recent years, he developed a noninvasive DNA-based test to determine if a fetus has chromosomal abnormalities that lead to diseases such as Down syndrome. More than half a million women are estimated to have taken the test in 2013.

Now, Quake and his team of researchers at Stanford University in California have gone a step further, developing a test that uses a small sample of a pregnant woman’s blood to monitor the RNA activity of a fetus at various stages throughout pregnancy. If the DNA test that’s already in use is compared to a photograph of life in the womb, the RNA test is more like a video.

Quake is cited as senior author of the research paper based on the RNA study; he’s a professor of applied physics and bioengineering at Stanford. Lead authors of the study are Winston Koh and Wenying Pan, both Stanford graduate students.

The unique combination of genetic material that every person receives from his or her parents makes each person completely unique themselves. Every cell in the body contains DNA, which doesn’t change over the course of a lifetime; the genes we’re born with are the genes we’ll die with.

How the body utilizes that DNA is the result of RNA, which remains active — dynamic — throughout life. As life progresses, DNA uses some RNA like a messenger to create the proteins necessary to cope with everyday events such as diet, exercise, stress, and exposure to toxins.

When a cell dies, it disintegrates, leaving some DNA and RNA remnants free to float through the bloodstream. When a woman is pregnant, some of the free-floating DNA and RNA in her bloodstream comes from her baby.

Quake used this free-floating DNA to develop his test for fetal chromosomal abnormalities. Testing the RNA has been a challenge, though, because there’s so little of it in the bloodstream. New technologies, however, require only a small sample for testing and make analysis so precise that maternal and fetal RNA can be identified separately. It’s so precise, Quake and his research team can identify which individual fetal organs the RNA came from and which came from the placenta.

When messenger RNA samples in the mother’s bloodstream are tested at various intervals over the course of a pregnancy, an ongoing assessment of the health of the fetus can be achieved as it changes over the course of gestation. Quake, who likens the RNA test to a “molecular stethoscope,” expects further study to lead to methods of identifying preeclampsia and other factors that contribute to premature birth and various complications of pregnancy. He also predicts using similar RNA tests to monitor Alzheimer’s disease, cancer, and the health of transplanted organs.


Source: Conger, Krista. “Monitoring RNA levels in blood samples yields dynamic picture of fetal development, disease, say researchers.” Stanford Medicine. Stanford School of Medicine. May 5, 2014. Web. May 19, 2014.