Fetoplacental chromosomal discrepancy

Area of Science:

• Genetics
• Prenatal Diagnosis
• Gynecology

Background:

• Chorionic villus sampling (CVS) is an alternative to amniocentesis for prenatal genetic diagnosis.
• Discrepancies between placental and fetal chromosomal constitution (fetoplacental discrepancies) pose diagnostic challenges.
• Understanding these discrepancies is crucial for accurate prenatal genetic counseling.

Purpose of the Study:

• To investigate the occurrence and implications of fetoplacental discrepancies identified during prenatal diagnosis.
• To analyze the correlation between placental chromosomal abnormalities and fetal development.
• To highlight the importance of further genetic testing when karyotype findings differ between placenta and amniotic fluid.

Main Methods:

• Retrospective analysis of 26 cases with identified fetoplacental discrepancies.
• Cytogenetic analysis of chorionic villi, amniotic fluid, and fetal blood samples.
• Evaluation of fetal development, including intrauterine growth retardation and uniparental disomy.

Main Results:

• Chromosomal aberrations were confined to the placenta in 21 out of 26 cases.
• In two cases, abnormalities were found in amniotic fluid and fetal blood but not in chorionic villi.
• Three cases with confined placental aneuploidy showed intrauterine growth retardation; four of six evaluated cases showed biparental inheritance for uniparental disomy.

Conclusions:

• Fetoplacental discrepancies, particularly confined placental aneuploidy, are associated with adverse fetal development.
• A positive correlation between placental aneuploidy and abnormal fetal development is supported.
• Further DNA analysis is essential when discrepant karyotype findings arise between placental and amniotic samples.