1. Prenatal Approach (Chromosomal) Shahram Savad MD, Medical Genetics

2. Who? Age! Family History! Consanguinity! Any Pregnant

3. Conventional Screening First Trimester Screening ( NT, Biochemical) Second Trimester Screening (Biochemical) Cell Free Fetal DNA

4. First Trimester Screening Low Risk Intermediate Screening High Risk

5. Second Trimester Screening Low Risk Intermediate Risk High Risk

6. Cell Free Fetal DNA Who? When? What? What's Wrong?

7. Cell Free Fetal DNA (screening test) Advantage? Very Good Screening Test ( Low F.P, Low F.N, High Detection Rate) Time Limitation Non Invasive

8. Cell Free Fetal DNA (screening test) Disadvantage? Only T21, T18, T13 Detected by this test? (Accuracy) Sex Determination, Sex Aneuploidy, Micro deletions? Other chromosomal abnormality

9. Prenatal Diagnosis of Chromosomal Disorders CVS Amniocentesis PUBS Fetoscopy

10. Different Types of Study Chromosomal Study Karyotype FISH Molecular Study QF-PCR MLPA

11. Chromosomal Study(Karyotype) Advantage 1.Assessment of all chromosomes. 2.Can detect mosaicism. 3.Only single test accept for legal abortion.

12. Down Syndrome Karyotype

13. Chromosomal Translocation

14. Chromosomal Study(Karyotype) Disadvantage Time ( about 12-18 Days) Cannot R/O single gene disorders.

15. Chromosomal Study(FISH) Advantages Time Disadvantages Legal Abortion False Negative Can not evaluate all chromosomes May be its not available

16. Down Syndrome (FISH)

17. Molecular Study(QF-PCR) Advantages Time 1-3 Working days Disadvantages Legal Abortion is not possible Can not R/O Mosaicism Can not evaluate all chromosomes

18. Down Syndrome (QF-PCR)

19. Molecular Study (MLPA) Advantages Time 2-3 Working days Disadvantages Legal Abortion is not possible Can not R/O Mosaicism Can not asses all chromosomes

20. High Risk For T21 in Screening May be Normal fetus. May be T21 or Down Syndrome. May have other chromosomal abnormality.

21. Case Report, Maternal Age:28, Quad. risk for Down: 1/20

22. Case Report, NT=2.5, Maternal Age:34, FTS risk for Down: 1/65 Cell Free Fetal DNA NORMAL Karyotype ( Inv. Of chromosome 7)

23. Thanks for your attention