During pregnancy, the placenta leaks fetal cell-free DNA (cfDNA) which circulates in the maternal bloodstream. As a result, a maternal blood sample contains a mixture of fetal and maternal circulating DNA. The Sage™ prenatal screen directly measures the amount of this cfDNA and can detect a small change in the DNA ratio between the maternal and cfDNA to estimate the risk of a fetal chromosomal aneuploidy or a microdeletion being present.
What does Sage screen for?
Sage™ has a menu-based approach to cfDNA screening. Following consultation with the pregnant mother, simply select the chromosomal disorders required. This gives clinicians the ability to meet specific patient considerations based on their background, maternal history and wishes.
The Sage™prenatal screen estimates the risk of a fetus having Down’s syndrome (Trisomy 21), Edwards' syndrome (Trisomy 18) and Patau’s syndrome (Trisomy 13). The accuracy is >99% for the detection of fetal chromosome aneuploidy. In addition, a complete autosomal aneuploidy detection analysis on the remaining chromosomes may be carried out and reported.
Sex chromosome aneuploidies
Upon request, the following sex chromosome aneuploidies can be screened for:
- Monosomy X – Turner syndrome
- XXX – Triple X syndrome
- XXY – Kleinfelter syndrome
- XYY – Jacob’s syndrome
Microdeletion syndrome is caused by the absence of a small portion of genetic material in the chromosome. They can vary greatly in severity, with the symptoms of microdeletions ranging from minimal developmental delays to severe anomalies e.g. cardiac defects, neurological malformations etc.
Upon request, the following microdeletions can be screened for:
- DiGeorge syndrome
- 1p36 deletion syndrome
- Prader-Willi syndrome
- Angelman syndrome
- Cri-du-Chat syndrome
- Wolf-Hirschhorn syndrome
Fetal sex determination
In regions where fetal sex determination is permitted and upon request, the fetal sex can be determined with >99.9% accuracy.