A new technique could make it possible to detect fetal abnormalities with a sample of the mother’s blood, instead of invasive procedures which can put the pregnancy at risk, researchers reported on Tuesday.
The new laboratory test uses formaldehyde to stabilize membranes in the blood cells of samples collected from the mother, thus increasing the amount of fetal DNA that can be examined.
Without such stabilization the DNA samples are often destroyed during collection, handling and processing, a problem that has limited the use of maternal blood samples to identify abnormalities such as Down Syndrome or spina bifida.
The test was developed by Ravgen Inc., a private biotechnology company based in Maryland which reported the results in an article published in this week’s Journal of the American Medical Association.
'Profound clinical implications'
Invasive prenatal tests with such techniques as amniocentesis or umbilical blood sampling are highly reliable, but carry a risk for loss of the pregnancy, the study said. As a result women who would otherwise be candidates for a diagnosis, such as those over age 35, decline them, the authors said.
In one part of its test, free fetal DNA in untreated blood samples averaged 7.7 percent compared to more than 20 percent in the treated samples, the company said.
A high percentage of free fetal DNA makes it easier to diagnose chromosomal abnormalities, the report said, and suggests that the technique could provide “a solid foundation for the development of a noninvasive prenatal diagnostic test.”
In an editorial in the same journal commenting on the study researchers at Baylor College of Medicine in Houston said the findings have major clinical implications.
“Developing a reliable, transportable technology for cell-free DNA analysis impacts two crucial areas -- prenatal genetic diagnosis and cancer detection and surveillance,” the editorial said.
“With prospective studies focusing on clinical applications of these findings, profound clinical implications could emerge for prenatal diagnosis and cancer surveillance,” it added. It could mean that leukemia, for example, could be monitored with a blood test instead of having to take a bone marrow sample, it said.
