Pengenalan mengenai prenatal diagnosis. Memberikan gambaran sekilas mengenai cara-cara untuk mengetahui kelainan bawaan sejak janin dalam kandungan. lebih ditujukan untuk kalangan medis. Non Invasive Prenatal Testing (NIPT)

1. Hendrik Sutopo
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2. Prenatal diagnosis
prenatal diagnosis is not to generate perfect babies.
“The are no perfect human specimens – we are all
genetically flawed in some way.”- F.Collins
The goal of prenatal diagnosis is to help parents learn what
they need to know about the health of their unborn child to
help them make informed decisions for themselves and their
family within the context of their own value system.
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3. Prenatal Diagnosis
1/300 pregnancies have
recognizable chromosomal
abnormalities
95% are Trisomy 21, 18, 13, or
changes in X and Y
Majority are Down syndrome
Screening for aneuploidy only?
Prenatal Genetic Test?

4. Genetics in Medicine
Human Genome Project has brought inherited
health factors to the forefront
Genetic risk assessment, screening and testing are
now part of primary care
Are we ready?
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5. Reproductive Genetic Risk
Assessment
May occur as part of preconception or
prenatal care
4 key assessment areas
Maternal age
Family medical history
Current pregnancy history
Ethnic background
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6. Carrier Frequencies Based on Ethnic
Origin
African-American Sickle Cell
Cystic Fibrosis
Beta-Thalassemia
1 in 10
1 in 65
1 in 75
Ashkenazi Jewish Gaucher disease
Cystic Fibrosis
Tay-Sachs disease
Dysautonomia
Canavan disease
1 in 15
1 in 26 – 1 in 29
1 in 30
1 in 32
1 in 40
Asian Alpha-Thalassemia
Beta-Thalassemia
1 in 20
1 in 50
European American Cystic Fibrosis 1 in 25 - 1 in 29
French Canadian, Cajun Tay Sachs disease 1 in 30
Hispanic Cystic Fibrosis
Beta-Thalassemia
1 in 46
1 in 30 - 1 in 50
Mediterranean Beta-Thalassemia
Cystic Fibrosis
Sickle Cell
1 in 25
1 in 29
1 in 40

7. Prenatal Diagnosis
Problems
What tests are AVAILABLE?
What tests should be OFFERED?
What tests should be RECOMMENDED?
Are the tests we performed is ENOUGH?
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9. Types of Tests
A. Screening tests
○ Cheap and safe tests suitable for whole population
○ Selects a subgroup for diagnostic testing
○ sensitivity and positive predictive value is important
B. Diagnostic tests
○ Have a high degree of accuracy
○ e.g. Amniocentesis for chromosomes
○ May be invasive, carry risk and expensive
Ultrasound can be used for both screening
and diagnosis
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10. A. Screening Options
1. First trimester
2. Second Trimester
3. Integrative screening
4. Sequential screening
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11. 1. First Trimester Screening
USG  NT (Nuchal translucency)
Biomarker/Serum screening
PAPP-A (pregnancy associated plasma protein-A)
hCG (human chorionic gonadotropin)
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12. Nuchal Translucency
Timing: 11-13+6 wks EGA
NT measurement > 3 mm
associated with
Chromosomal abnormalities
Structural anomalies
SGA, stillbirth
Down syndrome
detection rate 64-70%
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13. Nuchal Translucency
The Genetics Education Project
Increased NT associated with:
 Trisomies 21, 18, 13, triploidy and
Turner syndrome
 Spontaneous fetal loss
 With normal chromosomes: cardiac
defects, diaphragmatic hernia,
pulmonary defects, skeletal
dysplasias, congenital infection,
metabolic/haem disorders, rare
single gene disorders
 Normal pregnancy – chance of a
normal birth varies with size of NT
measurement
Nicolaides. Am J Obstet Gynecol 2004;191:45
Souka et al. Ultrasound Onstet Gyncol 2001;18:9
NT
measurement
Chance of
normal birth
≤ 3.4mm 95%
3.5 – 4.4mm 70-86%
4.5 – 5.4mm 50-77%
5.5 – 6.4mm 67%
≥ 6.5mm 31%

14. 1st Trimester Serum Screening
Timing: EGA 9 to 13+6 wks
Analytes used
Free b-hCG
PAPP-A
Detection rates
Trisomy 21: 68 %
Trisomy 18: 90%
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15. Down syndrome DR ~1:270 Cut-off
FPR DR
MA + NT1 10% 71%
MA + Biochemistry3 ? 67%
MA + NT +
Biochemistry2 5% 84-87%
1. Schuchter et al. Prenatal Diagnosis 22: 211, 2002
2. Wapner et al. NEJM 349: 1405, 2003
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3. Spencer et al UOG 1999

16. 2. Second Trimester Screening
Triple screen
Quadruple screen
Genetic sonogram
Extended sonogram: serum + ultrasound markers
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17. Triple screen
Used for Down Synd. Screening. It comprises
. AFP
. hCG
. uE3 (unconjugated oestriol )
- Best carried at 15-18 weeks.
- Triple test + maternal age diagnose +60% DS
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19. Quad Screen
Analytes used (with maternal age)
Alpha-fetoprotein (AFP)
Unconjugated estriol (uE3)
Beta-human chorionic gonadotropin (b-HCG)
Dimeric inhibin-A
Detection rates
Trisomy 21 : 75-80% (vs +60% with triple screen)
Trisomy 18 : 60 %
NTD : 75-80 %
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20. Screening Procedures --- Cont.
Ultrasonography:
- Screening tool in all trimesters
- At 10-14 weeks if fetal nuchal translucency > 3 mm 
chromosomal anomalies association
- At 18-20 weeks 75% fetal abnormalities can be diagnosed
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21. Comparison of PN Screening Tests in
Detecting Down Syndrome
Test Detection Rate
(DR)
False Positive
Rate (FPR)
IPS 85 - 95% 1 - 4%
FTS 84 - 87% 3 - 6%
Quad 75 - 85% 5 - 10%
Triple 60 - 85% 5 - 12%
NT alone 60 - 70% 5%
False positive rate lower with a dating ultrasound

22. 4. Sequential screening
Independent
Independent interpretation of FTS & STS
Not recommended
Step-Wise
FTS <cut of point  STS
If FTS >cut of point  invasive test (i.e. CVS)
Contingent
FTS <low cut of point  no further screening
If FTS in between  STS
If FTS >high cut of point invasive test (i.e. CVS)
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23. B. Diagnostic tests
Invasive
Amniocentesis
CVS
Fetal Blood Sampling
Embryoscopy & Fetoscopy
Non-invasive
USG
Preimplantation Genetic Diagnosis
Fetal Cells in Maternal Circulation
Cell-free Fetal DNA
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24. Amniocentesis
Diagnose > 100 disorders, cells analyzed for
chromosomal and biochemical disorders
Risk of infection and spontaneous abortion
Normally only used when:
Advanced maternal age
History of chromosomal disorder
Parent with chromosomal abnormality
Mother carrier of X-linked disorder
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25. p. 46
Removal of about
20 ml of amniotic
fluid containing
suspended cells
that were sloughed
off from the fetus
Biochemical analysis
of the amniotic fluid
after the fetal cells
are separated out
Centrifugation
Fetal cells
are removed
from the
solution
Analysis of fetal cells
to determine sex
Cells are
grown in an
incubator
Karyotype analysis
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26. Chorionic Villus Sampling
(CVS)
Done for similar reasons as amniocentesis
Performed earlier than amniocentesis
6–10 weeks vs. 16 weeks
Karyotypes available within a few hours or days
Increased risk of spontaneous abortion (.5–2%)
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27. CVS Procedures
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29. FETAL BLOOD SAMPLING
(FBS)
• cordocentesis
• Fetal blood-lymphocyte are rapidly cultured (~48-72 hours)
• Indications:
• 1- Prenatal Dx. DNA available for Cytogenetic studies In failed
amniocentesis, and mosaicism in chorion or amniotic fluid
• 2-Fetal assessment: for red cell alloimmunization, Hydrops fetalis,
viral infection, platelets alloimmunization
• Currently used for blood transfusion in-utero.
• Suitable time is 20-28 weeks
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30. FETAL BLOOD SAMPLING
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32. Prenatal Diagnosis?
VS
Prenatal Genetic Testing ?
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37. Prenatal Genetic Testing..
More than just conventional prenatal diagnosis
Detect genetic disorders and birth defects
> 200 single gene disorders can be diagnosed
Testing done only when a family history or other risk
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38. Genetic Disorders
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39. EMBRYOSCOPY &
FETOSCOPY
Direct visualization of embryo and fetus.
Limited field of vision.
Provide information only about external fetal structures.
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40. Amnion (stuck twin)
Umbilical cord
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41. B. Diagnostic tests
Invasive
Amniocentesis
CVS
Fetal Blood Sampling
Embryoscopy & Fetoscopy
Non-invasive
USG
Pre-implantation Genetic Diagnosis
Fetal Cells in Maternal Circulation
Cell-free Fetal DNA
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42. NON INVASIVE TESTS
• Ultrasonography
• Diagnostic USG is different from screening USG,
- It takes longer time
- Wide range of c. anomalies
- Non invasive and diagnosis at spot possible
- possible only at large gestational age
• Colour doppler further enhance the capability especially
for cardiac malformations and renal agenesis.
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43. Woman Having an
Ultrasound
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44. Preimplantation Genetic Diagnosis
(PGD)
Eggs collected, fertilized, allowed to develop
~Third day of fertilization, embryo has 6–8 cells
one cell, a blastomere, is removed, DNA extracted
and tested
Embryo without genetic disorder are implanted into
mother
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45. DNA Diagnosis
Uterine Implantation
In vitro Fertilization and Preimplantation Diagnosis
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46. Fetal Cells in Maternal
Circulation
Types
Placental cells
White blood cells
Immature red blood cells with nuclei
Enter the bloodstream (~6 and 12 weeks)
Fetal cells, only 1/100,000 in mother’s blood
Techniques need to be developed
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47. Cell-free Fetal DNA in maternal
plasma
As cells turnover, chromosomes fragment releasing DNA into the
blood
Cell-free DNA (cfDNA) are short DNA fragments (50-300 base
pairs)
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52. Results Section
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58. 2007 Updated ACOG Recommendations
(Level A) Practice Bulletin #77
Combined 1st trimester screening is an effective
screening test, better than NT alone
Women with positive first trimester screens should be
offered counseling and an option of CVS or 2nd
trimester amniocentesis
Neural tube screening should be offered to all women
who elect first trimester aneuploidy screening
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59. THANK YOU
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60. QUESTIONS ??
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61. EBM Recommendation # 1
Women at high risk for fetal aneuploidy
(age > 35 at time of delivery or prior
child/fetus with aneuploidy) should be
offered genetic counseling
Strength of evidence: B
Source: National Guideline Clearinghouse
www.guideline.gov
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62. EBM Recommendation Update
“Screening & invasive diagnostic testing
for aneuploidy should be available to all
women who present for prenatal care
before 20 wks of gestation regardless of
age”
Source: ACOG Practice Bulletin #77
(1/07)
Strength of evidence: B
Source: National Guideline Clearinghouse
www.guideline.gov
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63. Reminder!
“Screening & invasive diagnostic testing
for aneuploidy should be available to all
women who present for prenatal care
before 20 wks of gestation regardless of
age. Women should be counseled
regarding the differences between
screening and invasive diagnostic
testing.”
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