Non-Invasive Prenatal Test (NIPT)
What Is Non-Invasive Prenatal Test (NIPT)?
In last fifteen years with the rapid developments in medicine and technology, genetic material called extra-cellular free fetal DNA of the baby has been examined in the maternal (mother's) bloodstream. Extracellular cell free fetal DNA is in the form of small particles and circulates freely in the maternal bloodstream. At this time, studies have been intensified and since 2012, cell free fetal DNA has entered the clinical practice for the detection of chromosomal abnormalities.
Cell-free foetal DNA can be defined as the DNA of the foetus that is observed in a pregnant woman’s bloodstream after the 5thweek of gestation. This is because of the breakdown of placental cells and this causes the genetic material of the foetus constantly being released into maternal bloodstream. Cell-free foetal DNA is outside the maternal cells in tiny particles and it streams freely in maternal blood. Fetal fraction rate ( The ratio of cell-free foetal DNA in maternal blood) is about 10% in between the 11thand 13thweeks of gestation. This ratio increases as pregnancy proceeds and is normally in between 3% to 20%.
Detection of chromosomal disorders can be performed by analyzing cell free fetal DNA from maternal blood and this method is accepted as screening test which called as ‘’Non-invasive Prenatal Screening Test’’ or Non-invasive Prenatal Test ” shortly called NIPT.
With NIPT it is possible to detect the increase in the foetal DNA particles in chromosome 13, chromosome 18, chromosome 21 and aneuploidy of sex chromosomes by using Next Generation DNA Sequencing method. By this method chromosomal disorders of Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18), Patau Syndrome (Trisomy 13), Turner Syndrome (XO), Triple X Syndrome (XXX), Klinefelter Syndrome (XXY), Jacobs Syndrome (XYY) can be screened safely for the mother and baby.
What Separates NIPT from Other Classic Prenatal Tests?
NIPT has been developed from the pre-existing non-invasive prenatal tests like serum screens and vasive techniques. In DNA-based molecular genetics studies, it is proved that several foetal trisomy risks can be determined with NIPT by maternal blood which makes NIPT a practical and reliable DNA test. On the other hand, chorionic villus biopsy (CVB) and amniocentesis requires penetrance to the womb; which increases the risk of miscarriage. NIPT does not have this risk for the baby and the mother since penetrance to the womb is not required and only 9 ml maternal blood is enough to examine the test.
How Reliable Is NIPT?
NIPT is generally used as a screening test for the detection of chromosome abnormalities that occur in a higher frequency; such as Trisomy 21 (T21), Trisomy 18 (T18), and Trisomy 13 (T13) where the accuracy of NIPT is about 99,9%.
If the test result comes out as negative, it means that the foetus does not have any disorders related to test’s extent and pregnancy proceeds. If the test comes out as positive, the result is confirmed with amniocentesis or cordocentesis before ending pregnancy.
Before the application of NIPT to the mother, the parents should be informed that; NIPT is applied only in the detection of T21, T18, T13 and sex chromosomes (not for twin) abnormalities and according to the clinical applications NIPT is not expected to detect other chromosomal abnormalities such as; other trisomies, monosomies, translocations, insertions, deletions and microdeletions. If the result of the test is positive the result should be further confirmed with amniocentesis and this information should be given to families with genetic counselling and the written consent form has to be signed for the test.
Is NIPT Applicable in Turkey?
NIPT is not applicable in Turkey blood samples are sent abroad to be examined. With the same method, NIPT is marketed under different brandnames in different countries. NIPT is marketed under the brand of; VisibiliT®, MaterniT21®, and Harmony®in USA, Panorama®in Canada, PrenaTest®in Germany , NIFTY®in China.
In Which Places Should NIPT Be Applied?
Since NIPT is a genetic test, it should be applied only in diagnostics centers for genetic diseases with a licence for DNA tests. The authority of drawing and sending blood for NIPT should only belong to such centers. If this test is applied in places other than such centers, the Ministry of Health should warn such companies.
To Who NIPT Should Be Applied?
NIPT should be applied to pregnant women who passed their 9thweek of gestation with one or more risk factors given below;
- Advanced maternal age (above 35)
- Abnormalities in serum biochemical reagent
- Abnormalities in ultrasound
- Existence of disorders which can be detected with prenatal screening in family members
- Presence of either a structural or numeral chromosomal abnormality in one of the parents
- Exposure to teratogenic and foetotoxic infections or agents
- Other risk factors
In our center, we apply CentoNIPT®. CentoNIPT® is a brand of German Company Centogene, a rare diseases company of biotechnology and diagnostics which is one of the biggest laboratories in Europe that study rare genetic diseases.
With CentoNIPT®, along with autosomal chromosomal abnormalities (such as Trisomy 21, Trisomy 18, and Trisomy 13), abnormalities in sex chromosomes (Turner Syndrome, Klinefelter Syndrome, XYY Syndrome, and Triple X Syndrome) can also be detected.
CentoNIPT®, which is completely safe for you and for your baby, is studied in 5 or 10 days with an expert clinical report with genetic counselling by our doctors.
For CentoNIPT®please contact with us.
