A new prenatal blood test made by Sequenom will test for Down syndrome less invasively in the early stages of pregnancy. Known as MaterniT21, the test determines with a high degree of accuracy whether the baby will have Down syndrome. This condition, in which the child has some degree of mental retardation, is caused by Trisomy-21 three copies of the chromosome 21, instead of the normal set of two.
A recent study, published in the journal Genetics and Medicine, demonstrates that the test is highly accurate, with an almost 99 percent detection rate, and a false-positive rate of only 0.2 percent. This test, if its accuracy is borne out in further studies, will provide an important alternative to the previous options of either amniocentesis or chorionic villus sampling, both of which are invasive and, on rare occasions, may cause premature labor and miscarriage.
MaterniT21 analyzes fetal DNA found in the mother s blood and determines whether the genome contains three copies of chromosome 21. The test can be effective as early as 11 weeks into the pregnancy.
Knowing whether a child will have Down syndrome allows parents to better prepare themselves for the challenges and special needs that may lie ahead. With about 83,000 U.S. children living with Down syndrome in 2002 and even more now, given that the frequency of Down syndrome births has been steadily increasing having a safe and highly effective test available would be important for many families.