By Keith S. Wexler, MBA, Maternal Feta Medicine, Prenatal Diagnosis and Biotech/Life Sciences Consultant, GENASSIST, Inc.
Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.
Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center
Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital
Background: The breakdown of fetal cells in the maternal circulation make it possible for laboratories to screen for Fetal DNA during pregnancy. When fetal cells break down Cell Free DNA (cf DNA) is released.
It is possible to duplicate many copies of this DNA so that testing is possible. This prenatal non-invasive testing can be performed as early as the 10th week of pregnancy.
(47,XXX )Trisomy X is characterized by an additional X chromosome in females instead of the expected two
X chromosomes. (Incidence approximately 1 in 1000 females).
(47,XXY) Klinefelter Syndrome is characterized by two X chromosomes and one Y chromosome in males instead of the expected one X and one Y chromosome. (Incidence approximately 1 in 800 males).
(47,XYY) is characterized by one X chromosome and two Y chromosomes in males instead of the expected one X and one Y chromosome. (Incidence approximately 1 in 800 males).
*Some Maternal Fetal DNA Panels require the XY component of the test to be added on by the healthcare provider in order to look for a sex chromosome abnormalities.
If a Maternal Fetal DNA test result comes back as “High Risk” for a chromosomal abnormality, the recommendation1 is to confirm the diagnosis by amniocentesis.