Fetal DNA Screening Tool Detects Down Syndrome With Mom's Blood
A new fetal Down syndrome screening which tests mother's blood for the condition, has been found highly effective and could soon replace existing screening protocol.
The screening tool was developed by researchers at the University of California, San Francisco. Done between 10 and 14 weeks of pregnancy, the test analyzes fetal DNA in maternal blood to determine chromosomal anomalies associated with the condition. Large quantities of fetal DNA in maternal serum was found to be a strong indicator of Down syndrome, which causes physical, mental and lifelong health problems, reports US News and World Report.
Researchers found that the screening test detected the condition in fetuses of all the 38 women, confirmed later. The study involved 16,000 women.
Testing involves amplifying free-cell DNA found in maternal blood and sequencing them compare relative amounts of DNA of each chromosome. The quantity was indicator of risk. Down syndrome is characterized by an extra copy of chromosome 21. Researchers however cautioned against using the screening for diagnosis.
"Those women who do opt for cell-free DNA testing should be informed that it is highly accurate for Down syndrome, but it focuses on a small number of chromosomal abnormalities and does not provide the comprehensive assessment available with other approaches," said study's author Mary Norton.
Researchers also claimed that the free-cell test produces far fewer false positive than existing ultrasound-blood marker tests combination. However they did mention that the test could miss the condition in women with inadequate amounts of free DNA.
