preimplantation genetic testing-viafet
TRANSCRIPT
Preimplantation Genetic Testing
Tools & Facilities
Ahmad Mustafa MetwalleyMSc, Molecular PathologyViafet- Dubai
PGT, is a technique used to identify genetic defectsin embryos .
Known as "embryo screening,"ART procedure followed by embryos cells isolation to be tested.To screen chromosomal or genetic abnormalities .
Introduction of PGT in IVF revolutionized ARTTo prevention of transmission of hereditary diseases and chromosomal abnormalities
Chromosomes• PGS: Preimplantation Genetic Screening
• CCS: Comprehensive Chromosomal Screening
Genes• PGD: Preimplantation Genetic Diagnosis
• PGH: Preimplantation Genetic Haplotyping
A- FISH : Fluorescence In Situ Hybridization - 13 ,18 ,21 ,X and Y
- Sex differentiation with normal embryos - Balanced chromosomal translocations
- Increases IVF output to :
Number of cases/Sac with Heart
≤36 >37
FISH day 3 34 / 67 = 51% 17 / 45 = 37%
FISH day 5 42 / 62 = 68% 20 / 34 = 59%
B- CCS: Comprehensive Chromosomal Screening - 24 chromosomes - CGH-Array, Ion Torrent and NGS - Identifying micro-deletions and translocations - Yang et al., 2012: RCT, CGH with SET incased IVF:
Number of cases/Sac with Heart
PGS - CCS No PGS
Array at day 5 39 / 55 = 71% 22 / 48 = 46%
Dose PGS helps recurrent abortion Patients?
Poor quality eggs associated with advanced maternal age is
associated with chromosomal abnormalities
Somatic chromosomal abnormalities are the main cause of
recurrent mischarge, recurrent failure.
Micro deletion or translocations can be screened simply by PGS
Sever male factor indicated for PGS
Preventing Hereditary Disease
Known also as single gene disorders
• Autosomal Recessive Disorders
• Autosomal Dominant Disorders
• X-linked Recessive Disorders
• Cancer Hereditary Disease
Ataxia Telangiectasia Sickle cell
Infantile Seizures Thalassemia
Breast Cancer Mediterranean Fever
Cholestasis G6PD
Galactosemia Hemophilia
Gaucher Disease DMD
Hunter Disease Cystic Fibrosis
Immunodeficiency Spinal Muscular Atrophy
Polycystic Kidney Metabolic disorders
Wolmann Disease Fragile X syndrome
Primary Hyperoxaluria Albinism
PGD-PCR or PGD-NGS is performed to differentiate affected,
carrier or healthy embryo for transfer from abnormally
genotyped parents.
Paternal mutations are required for screening prior to cycle
....Step to avoid abnormality inheritanceAs well as Gender Selection……
Also, HLA compatibility testing….
• Bone Marrow transplantation
• Stem cells utilities
• Organs transplantation
• provides All PGT investigations
within 48 hours between Day3 biopsy and Day5 prepared for ET.
• provides whole case management not single embryos.
• unsuccessful embryos assessment is prepared for retesting.
• ExactCCS and Luminscent are unique to give highest accuracy
and shortest TAT.
• Also, Non Invasive prenatal testing
NIPT, Non Invasive Prenatal Testing….
• Amniocentesis with accepted risk of infection or abortion
• CVS is more aggressive with increased risks
• Triple marker or Double marker are accepted but not promising
• Re-aspiration or resampling is expected
• Advanced gestational weeks are problematic
• NIPT is only Maternal blood at Week 11.
• Result within 10 days for 24 chromosomes with 100 % accuracy