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Semiconductor Sequencing for Preimplantation Genetic Testing for Aneuploidy
Published on: August 25, 2019
Aneuploidy in the human cleavage stage embryo
A Mantzouratou1, J D A Delhanty
1Fetal and Maternal Medicine, Institute for Women's Health, University College London, London, UK.
Cytogenetic and Genome Research
|February 5, 2011
Summary
Early human embryos frequently exhibit chromosomal abnormalities, particularly mosaicism, impacting development. These errors stem from the cleavage stage cell cycle and parental genetic factors.
Area of Science:
- Reproductive Biology
- Human Genetics
- Developmental Biology
Background:
- Cleavage stage human embryos (days 1-3) exhibit high rates of chromosomal anomalies, notably mosaicism, before embryonic genome activation.
- Molecular cytogenetics reveals approximately 60% of in vitro derived embryos possess aneuploid cells by day 3, yet 25% show no aneuploid cells upon comprehensive single-cell analysis.
Purpose of the Study:
- To investigate the mechanisms underlying the high incidence of chromosomal anomalies in early human embryos.
- To understand the impact of mosaicism versus uniform aneuploidy on embryonic development and implantation potential.
Main Methods:
- Molecular cytogenetic analysis of individual cells within cleavage stage embryos.
- Pre-implantation genetic aneuploidy screening (PGT-A) follow-up studies.
Main Results:
- Extensive mosaicism affecting multiple chromosomes appears to hinder development more than uniform aneuploidy.
- Meiotic error frequencies vary by referral reason, with recurrent miscarriage showing the highest rates and repeated implantation failure the lowest.
- The high incidence of anomalies results from the error-prone cleavage stage cell cycle and parental predisposition to chromosomal instability.
Conclusions:
- Chromosomal anomalies in early human embryos are multifactorial, involving embryonic cell cycle dynamics and parental genetic factors.
- Mosaicism is a significant factor affecting embryonic development and implantation success.
- Understanding these mechanisms is crucial for improving assisted reproductive technologies and managing infertility.
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