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Distribution of mosaicism in human placentae
K G Henderson1, T E Shaw, I J Barrett
1Cytogenetics Laboratory, Department of Pathology, B.C. Children's Hospital, Vancouver, Canada.
Human Genetics
|May 1, 1996
Summary
Confined placental mosaicism (CPM), detected in 2% of prenatal diagnoses, requires analyzing both placental tissues. This study examined nine placentae, confirming CPM and revealing tissue-specific patterns for better understanding fetal effects.
Area of Science:
- Reproductive biology
- Human genetics
- Prenatal diagnostics
Background:
- Confined placental mosaicism (CPM) occurs in approximately 2% of pregnancies undergoing chorionic villus sampling (CVS).
- CPM involves genetic discrepancies between fetal and placental tissues, potentially impacting fetal development.
- Cytogenetic analysis of placental tissues is crucial for diagnosing and understanding CPM.
Purpose of the Study:
- To investigate the cytogenetic characteristics of term placentae from pregnancies with prenatally diagnosed CPM.
- To determine the distribution and patterns of mosaicism within placental tissues.
Main Methods:
- Collection and cytogenetic analysis (interphase and metaphase) of multiple biopsies from nine term placentae.
- Examination of both cytotrophoblast and villous stroma for aneuploid cell lines.
Main Results:
- Confined placental mosaicism (CPM) was confirmed in all nine placentae studied.
- Aneuploid cell lines included trisomies for chromosomes 7, 9, 16, and X.
- Distinct tissue-specific and site-specific patterns of mosaicism were observed.
Conclusions:
- Analysis of multiple placental biopsies, encompassing both cytotrophoblast and villous stroma, is essential for accurate CPM assessment.
- Understanding CPM's evolution and fetal impact necessitates comprehensive cytogenetic evaluation of placental tissues.