DNA-based prenatal blood test can also identify trisomy 13 and 18

Trisomy 18, also called Edwards syndrome, is a serious disorder with up to 70% of first trimester affected fetuses being spontaneously lost during pregnancies. Among those born alive, half die within a week with only 5% surviving the first year. All have serious medical and developmental problems. About 1,330 infants with trisomy 18 would be born in the US each year in the absence of prenatal diagnosis. Trisomy 13, also called Patau syndrome, is less common but equally serious. About 600 infants with trisomy 13 would be born in the US each year in the absence of prenatal diagnosis. Like Down syndrome, trisomy 18 and trisomy 13 are more common as maternal age increases. For comparison, about 7,730 Down syndrome cases would be born each year in the absence of prenatal diagnosis. Current prenatal screening tests for trisomy 18 and trisomy 13 rely on both biochemical and ultrasound markers. For more information visit the US National Library of Medicine PubMed Health.

This industry-sponsored project, awarded to Drs. Palomaki and Canick and Women & Infants Hospital in 2008, enrolled 4,500 women at 27 prenatal diagnostic centers throughout the world. Women & Infants also served as one of the enrollment centers under the direction of maternal-fetal medicine specialist and director of Perinatal Genetics, Barbara O'Brien, MD.

"It is clinically more relevant that all three trisomies can be detected by this test," said Dr. O'Brien. "Having access to such a comprehensive, DNA-based test that can be done early in pregnancy will give us more information so that we can better guide which patients should consider diagnostic testing."

Source: Women & Infants Hospital