Testing for Down syndrome may get much safer in the near futureA new study out from Stanford (yay Stanford!) promises to revolutionize prenatal testing. Instead of looking at a fetus’ cells, the test looks at mom’s blood. More specifically, it looks at the small amounts of fetal DNA found in her blood.
This test will get around the small but very real risk of miscarriage that comes with more invasive forms of testing like amniocentesis. Instead of inserting a needle through mom’s belly and into the amniotic sac, a doctor will insert a needle into her arm. This is obviously much safer for the fetus.
The test won’t be able to find everything though. It can’t find subtle genetic mutations like those that cause cystic fibrosis or sickle cell anemia.
What the test can do is identify fetuses with extra chromosomes. This is one of the main reasons women get prenatal testing--to screen for diseases like Down, Edward's or Patau syndrome. Each one of these is due to an extra chromosome that the test can detect.
The test is actually marvelously simple. A sample of blood is taken from mom and the cells are removed. The researchers then take a close look at the DNA that is left behind. Most of this DNA comes from mom but some comes from the fetus too.