1. NON – INVASIVE PRENATAL TESTING
NIPT
NON – INVASIVE PRENATAL TESTING
GENDIA
Antwerp, Belgium

2. NIPT www.DOWNsyndromeNIPT.info NON – INVASIVE PRENATAL TESTING
Testing of cff DNA (cell free fetal DNA)
from maternal blood during pregnancy
for trisomy 21, 18 and 13

3. 3

4. Frequency aneuploidies
Aneuploidy
Syndrome
Frequency (live births)
Trisomy 21
Down syndrome
1 in 700
Trisomy 18
Edwards syndrome
1 in 5,000
Trisomy 13
Patau syndrome
1 in 16,000

5. Trisomy 21, 18, 13 screening
Trisomy 21 (Down syndrome) Trisomy 18 (Edwards syndrome) Trisomy 13 (Patau syndrome)

6. History Down syndrome screening
1980 : Amniocentesis (advanced maternal age)
1990 : Triple screening (T21, T18 and T13)
2000 : First trimester screening (T21, T18 and T13)
2012 : First trimester screening + NIPT (T21, T18 and T13)
2015 : NIPT (extensive genetic screening)

7. Risk Down syndrome versus Maternal Age
Frequency (live births)
< 35
< 0.3 % 37
0.5 % 40
1 % 50
10 %

8. Serum Down syndrome screening
Triple screening ( > 1990)
Maternal age
Serum : AFP, HCG, free oestriol
Combi test ( > 2000)
Nuchal translucency (NT)
Serum : free B-HCG, PAPP-A

9. Classical Down syndrome screening First trimester serum screening (combi test)
Risk calculated from :
Maternal age : the higher the age, the higher the risk of T21, T18, T13
Nuchal translucency (NT) : the higher the NT, the higher the risk of T21, T18, T13
Serum parameters PAPP-A and free B HCG

11. NIPT history 1997 : Lo et al. :cff DNA in maternal circulation
2001 : Fetal Rh(D) genotype
2006 : Sexing fetus for :
X-linked genetic disorders
Sexing (China)
2011 : Detection trisomy 21/18/13
2012 : > patients screened in China / USA
2013 : Daily > 2000 NIPT tests worldwide

12. NIPT essentials
1. DESCRIPTION: NIPT is a DNA test on maternal blood to screen pregnancies for the most common fetal chromosome anomalies : trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome), with optional sexing. 2. SAMPLE: Specific test kits provided by GENDIA are required: 20 ml blood in specific blood tubes is required from the mother. The samples have to be sent by Express mail to GENDIA's lab in Antwerp (Belgium), and arrive there within 2 days of withdrawal.
3. TIMING: From gestation week TURNAROUND TIME: < 2 weeks 5. RELIABILITY: The reliability of NIPT is very high (more than 99% for trisomy 21). 6. INDICATIONS: Although NIPT can be performed in every pregnancy, it is especially indicated:
If the triple test or first trimester screening indicates an increased risk for Down syndrome or trisomy 18
Advanced maternal age
Anxiety for invasive procedures
7. CONTRAINDICATIONS: NIPT is not the test of choice when there is:
Fetal anomalies on ultrasound
Known genetic anomalies that cannot be diagnosed by NIPT
A triplet pregnancy or vanished twin
8. PRICE: 690 Euro

13. Cell Free Fetal DNA (cff DNA) in Maternal Blood13

14. NIPT cff DNA < 1 % of total DNA in maternal circulation is fetal
5-30 % of cell-free DNA in maternal circulation is fetal

15. NIPT for trisomy 21 NIPT measures the ratio of chromosome 21 sequence
versus control chromosome sequence
to exclude trisomy 21

16. NIPT cffDNA
cffDNA
DNA Nl
T21 Nl
T21
Fetal
Maternal
< 1 of

17. Importance of fetal fraction
Expected ratio for Trisomy 4%
1.02
10%
1.05
20%
1.10
40%
1.20
Fetal cfDNA
Maternal
cfDNA
Reference Chromosome
Chromosome 21 17

18. NIPT reliability Test : Trisomy 21, 18, 13 Specificity : > 99 %
Sensitivity :
T21 > 99 %
T18 > 97 %
T13 > 80 %

19. NO NIPT for sex aneuploidies
Phenotype for sex aneuploidies is highly variable
Mosaicism in the fetus is a problem
Mosaicism in the mother is a problem
NIPT for sex aneuploidies is less accurate 19

20. NIPT Indications NIPT is the test of choice when there is :
Increased maternal age
Increased risk on Combination or triple test
Anxiety for invasive procedure (AC / CVS)

21. NIPT Contra indications
NIPT is NOT the test of choice when there is :
Fetal anomalies on ultrasound
A triplet pregnancy
Vanished twin
Known genetic anomalies that cannot be diagnosed by NIPT

22. NIPT Advantages versus combi test with AC / CVS
High sensitivity (few false-negatives)
High specificity (few false-positives)
More than T21
Non-invasive : no fetal risk
CVS : Risk of miscarriage : 1-2 %
AC : Risk of miscarriage : 0.5 %

23. NIPT Disadvantages Expensive (690 Euro) Only testing 5 chromosomes
Combi test : 150 Euro
Combitest + AC + karyotype : 1000 Euro?
Only testing 5 chromosomes
Failure rate : 3 %
Specific kits
Not available everywhere

24. Companies offering NIPT
ARIOSA (US)
VERINATA (US)
NATERA (US)
SEQUENOM (US)
BGI (China)
LIFE-CODEXX (Germany)

25. GENDIA offers the HARMONY test from ARIOSA
ARIOSA (Harmony)

26. NIPT results 1. Normal result : no specific follow up necessary,
unless ultrasound examination of the fetus reveals anomalies
2. Test failure : in 3 % pregnancies not enough fetal DNA :
NIPT repeated at no extra cost.
3. Abnormal NIPT result : amniocentesis or chorion biopsy

27. NIPT failures If less than 4 % of cf DNA is fetal
High amounts of maternal cf DNA :
Maternal obesitas
Low amounts of fetal cf DNA :
Trisomy 18
Triploidy ??

28. NIPT versus classical Down syndrome screening
Classical NIPT
False negatives % %
False positives 5 % (> 95 % of positives) < 0.1 %
Result > Week 13 > Week 12
Price euro Euro

29. NIPT versus classical screening in a country with 10 million inhabitants
Classical NIPT
Number screenings
Expected T (1/500) (1/500)
Detection rate 73 % > 99 % T
False negatives < 1
False positives < 100
Iatrogenic miscarriages

30. NIPT versus CVS / AC CVS / AC NIPT High risk : 25-50 %
(Monogenic disorder)
Medium risk : 5-10 %
(chromosomal anomaly)
Ultrasound anomaly (NT)
NIPT
Low risk < 5 %

31. NIPT : the future 1. Array CGH 2. Detection common monogenic mutations
All chromosomes
Small deletions - duplications
2. Detection common monogenic mutations
- CF
3. Whole exome / genome sequencing

32. Message in a bottle
1. DESCRIPTION: NIPT is a DNA test on maternal blood to screen pregnancies for the most common fetal chromosome anomalies : trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome), with optional sexing. 2. SAMPLE: Specific test kits provided by GENDIA are required: 20 ml blood in specific blood tubes is required from the mother. The samples have to be sent by Express mail to GENDIA's lab in Antwerp (Belgium), and arrive there within 2 days of withdrawal.
3. TIMING: From gestation week TURNAROUND TIME: < 2 weeks 5. RELIABILITY: The reliability of NIPT is very high (more than 99% for trisomy 21). 6. INDICATIONS: Although NIPT can be performed in every pregnancy, it is especially indicated:
If the triple test or first trimester screening indicates an increased risk for Down syndrome or trisomy 18
Advanced maternal age
Anxiety for invasive procedures
7. CONTRAINDICATIONS: NIPT is not the test of choice when there is:
Fetal anomalies on ultrasound
Known genetic anomalies that cannot be diagnosed by NIPT
A triplet pregnancy or vanished twin
8. PRICE: 690 Euro