Despite the study's limitations, the implications for prenatal diagnosis of genetic disease are profound, asserts Yuet Wai Kan of the Howard Hughes Medical Institute at the University of California, San Francisco. Kan and his colleagues report their findings in the November Nature Genetics. David L. Rimoin of the University of California, Los Angeles, School of Medicine says that such a test, if it lives up to expectations, could usher in a new era of prenatal diagnosis. Just 30 years ago, prenatal diagnosis did not exist. Now, amniocentesis and chorionic villus sampling can tell expectant parents whether their child will be born with sickle-cell anemia, thalassemia, or certain other genetic diseases.
Parents can then decide whether to continue the pregnancy.
These diagnostic procedures carry slight risks because they require doctors to invade the uterus with a slender needle to obtain fetal cells. Amniocentesis provokes miscarriage in a fraction of 1 percent of cases. Chorionic villus sampling causes miscarriage about 1 percent of the time. Using maternal blood would eliminate those risks, Rimoin says. The Kan study was inspired, in part, by research showing that fetal cells circulate in a mother's blood.