NIPT – TRISOMY

Non invasive diagnosis of Down syndrome from the blood of the mother

 

Summary:

Our laboratory was one of the first in the Czech Republic that introduced the  non-invasive prenatal TRISOMY NIPT test.   

Methodology:

Free DNA fragments are released from the placenta into the mother’s blood from the beginning of pregnancy. These fragments can be examined  using modern NGS (Next Generation Sequencing) techniques. Millions of free DNA fragments in maternal blood are analyzed. The relative frequency of the fragments is assessed by bioinformatic analysis. Trisomy is y likely with a statistically significant increase in fragment frequency from a particular chromosome.

 

Efficiency:

This  method of fetal free DNA testing in maternal blood diagnoses fetal trisomy  21, 18 and 13 with a sensitivity above 99%. The reliability of trisomy 21, 18, 13 is comparable to invasive fetal examination methods.

Positive result has to be verified by invasive examination.

Indication:

TRISOMY NIPT  may be indicated after the 10th week of pregnancy at:

    Increased risk of chromosome trisomy 21, 13 and 18 in screening test
    Atypical borderline screening result
    Age over 35 years.
    Concerns about the fate of pregnancy.
    Suspected family anamnesis

TRISOMY test XY

is an extended version of the TRISOMY test.

Detects the risk of complete trisomy of chromosomes 21, 18 and 13, fetal chromosomal sex and disorders number of sex chromosomes.

TRISOMY NIPT  test limitations

Trisomies  ares the cause of only 1% of birth defects in newborns, so TRISOMY  NIPT  is not a universal prenatal test to rule out all congenital developmental defects (clefts, heart defects, brain development…).

The results of this test may be distorted by maternal chromosomal aberration, low fetal fraction, fetal mosaic.

The assay is not suitable within 6 months after transfusion or stem cell transplantation.

 

Organization of examination:

Blood collection for TRISOMY examination is best performed after ordering at theCenter for  Prenatal  Diagnosis ( +420 542 442 17140) . The part of this examination can be  an interview with the a clinical geneticist who will consider the suitability of this examination and interpret the results.  We call the results to the patient and will be avaliable  on our www. prenatal.cz

The price of this examination also includes a careful ultrasound examination on the day of collection focused on ev. markers of chromosomal aberrations. If an ultrasound marker of chromosomal aberration is found (increased value of nuchal clarification), an invasive fetal examination – chorionic villi collection or amniotic fluid collection – is indicated instead of NIPT.

To exclude cardiac and cleft defects as well as overall evaluation of fetal development, it is advisable to complete a careful ultrasound examination at the 21st week of pregnancy.