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Trisomy 5 mosaicism in amniotic fluid with normal outcome
A C Casamassima1, P L Wilmot, M J Mahoney
1Department of Pediatrics, New York Medical College, Valhalla, New York.
Clinical Genetics
|April 1, 1989
Summary
A rare case of true mosaicism for trisomy 5, detected via amniocentesis but not fetal blood sampling, resulted in a normal outcome. This highlights the need for careful interpretation of prenatal genetic testing results.
Area of Science:
- Genetics
- Prenatal Diagnosis
- Human Chromosome Abnormalities
Background:
- Prenatal diagnosis of chromosomal abnormalities is crucial for assessing fetal health.
- True mosaicism, where cell lines with different chromosome complements coexist, presents diagnostic challenges.
- Trisomy 5 is a rare chromosomal condition with variable clinical manifestations.
Purpose of the Study:
- To present a case of prenatally diagnosed true mosaicism for trisomy 5.
- To discuss the discrepancy between amniocentesis and fetal blood sampling findings.
- To emphasize the importance of cautious interpretation of prenatal genetic testing results.
Main Methods:
- Prenatal diagnosis using amniocentesis.
- Karyotyping of amniotic fluid cells.
- Fetal blood sampling and subsequent karyotyping.
- Clinical follow-up of the neonate.
Main Results:
- Amniocentesis detected trisomy 5 in 23% of cells.
- Fetal blood sampling did not detect trisomy 5.
- The child was born clinically normal, with no apparent effects of trisomy 5.
Conclusions:
- Prenatal diagnosis of true mosaicism can be complex, with potential discrepancies between different sampling methods.
- A finding of mosaicism in amniotic fluid does not always reflect the fetal karyotype.
- Careful consideration and potentially further investigation are warranted when interpreting mosaic findings in prenatal genetic testing.