Rewriting Life

Blood Test for Down Syndrome

Apr 21, 2009

Tests currently used to determine whether an unborn child has Down syndrome carry a small risk of miscarriage, but a new test for the genetic abnormality could solve that problem by getting results from a maternal blood sample. The test, expected on the market this year, analyzes fetal RNA and DNA in the maternal blood serum for specific genetic markers found on chromosome 21. The number of copies of each of these markers reveals whether the fetal DNA has an extra copy of the chromosome–the genetic variation that causes Down syndrome.