Study Validates Use of Noninvasive Test for Defective Fetal Chromosomes

By LabMedica International staff writers
Posted on 13 Dec 2015

A German biomedical company has reported the successful validation of its qPCR (quantitative real-time PCR)-based noninvasive test for fetal genetic abnormalities such as trisomy 21 (Down's syndrome).

LifeCodexx AG (Konstanz, Germany) recently announced that its qPCR-based PrenaTest had been successfully validated in a study of nearly 700 samples of maternal blood.

$Image: Karyotype for trisomy 21 or Down\'s syndrome: the image clearly shows the three copies of chromosome 21 (Photo courtesy of Wikimedia Commons).$

Image: Karyotype for trisomy 21 or Down\'s syndrome: the image clearly shows the three copies of chromosome 21 (Photo courtesy of Wikimedia Commons).

Starting from the ninth week of pregnancy, the PrenaTest is able to determine trisomy 21, trisomies 21, 18, and 13, as well as gonosomal aneuploidies (Turner, triple X, Klinefelter, and XYY syndromes), in blood samples from expectant mothers at risk for fetal aneuploidies. If desired, the gender of the child may also be determined. This assay acts as a supplement to the noninvasive prenatal diagnostic techniques already in use, but—in comparison with invasive examination methods—it does not involve the risk of procedure-related miscarriage.

The test method of the PrenaTest is based on the analysis of cell-free DNA (cfDNA) in the pregnant woman’s blood. The cfDNA is present in fragments and freely circulates in the maternal blood. In addition to maternal cfDNA, the blood also contains approximately 2%–40% (on average approximately 10%) cell-free fetal DNA (cffDNA). The cffDNA essentially comes from the cytotrophoblast, that is, from placental cells of the growing embryo and is thus of extra-embryonic origin. It develops through apoptosis and necrosis of the trophoblast cells and is continually excreted into the pregnant woman’s bloodstream. The lifespan of the DNA fragments is about two hours. Within a few hours after birth of the child, the cffDNA is no longer detectable in the mother’s blood. With the PrenaTest, the cffDNA in the maternal blood is used to determine whether there is a chromosomal imbalance for a particular chromosome to thus determine a corresponding chromosomal disorder in the unborn child. Prenatal tests based on this method are known as noninvasive prenatal testing (NIPT).

The data generated by the clinical validation study was presented on the occasion of the FMF (Fetal Medicine Foundation) Advances Course held December 5-6, 2015, in London (United Kingdom).

“For the first time leading medical associations in Europe recently recommended that NIPT can now be used as primary screening for fetal trisomy 21 in all pregnant women of any age or risk,” said Dr. Wera Hofmann, CSO of LifeCodexx AG. “Due to its rapid turnaround time and low cost, our qPCR-based PrenaTest will be the ideal noninvasive prenatal test which will allow doctors to implement the new recommendations into their clinical routine.”

Related Links:
LifeCodexx AG