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The phenotype in placental trisomy 7.
A J Watt1, F J Devereux, N A Monk
1Department of Pathology Services, Dunedin Hospital, New Zealand.
Summary
Mosaic trisomy 7 detected during chorionic villus sampling in a normal pregnancy typically indicates a normal fetal karyotype. Placental function, structure, and growth remain unaffected, ensuring a healthy outcome for the baby.
Area of Science:
- Genetics
- Prenatal Diagnosis
- Human Reproduction
Background:
- Chorionic villus sampling (CVS) is a common prenatal diagnostic tool.
- Mosaic trisomy 7 is a chromosomal abnormality where some cells have an extra copy of chromosome 7.
Observation:
- A case of mosaic trisomy 7 was identified via CVS in an ultrasonographically normal pregnancy.
- The pregnancy was monitored and progressed without complications.
Findings:
- Mosaic trisomy 7 was confirmed in the term placenta.
- The placenta showed no structural abnormalities.
- The infant was phenotypically normal with a 46,XY karyotype.
Implications:
- Prenatal detection of mosaic trisomy 7 in normal pregnancies often correlates with a normal fetal karyotype.
- Placental development and function are typically not compromised in such cases.
- This suggests a favorable prognosis for pregnancies with mosaic trisomy 7 detected by CVS when the fetus is otherwise normal.