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Updated: Jun 23, 2026
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FISH for Pre-implantation Genetic Diagnosis
Published on: February 23, 2011
Handling small supernumerary marker chromosomes in prenatal diagnostics
Thomas Liehr1, Elisabeth Ewers, Nadezda Kosyakova
1Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany.
Expert Review of Molecular Diagnostics
|May 14, 2009
Summary
Small supernumerary marker chromosomes (sSMCs) affect millions globally. Improved prenatal diagnostics using advanced technologies can help identify sSMCs accurately, potentially reducing unnecessary pregnancy terminations.
Area of Science:
- Genetics and Genomics
- Prenatal Diagnostics
- Human Chromosome Research
Background:
- Small supernumerary marker chromosomes (sSMCs) are abnormal chromosomes, smaller than chromosome 20, challenging to characterize with conventional methods.
- sSMCs are found in 0.075% of prenatal cases and affect approximately 3 million individuals worldwide.
- Prenatal detection of sSMCs, especially with ultrasound abnormalities (0.2% of cases), often leads to pregnancy termination, even when sSMCs have no phenotypic effects in ~70% of de novo cases.
Purpose of the Study:
- To provide an overview of current state-of-the-art technologies for sSMC analysis.
- To highlight methods for optimizing sSMC analysis in prenatal diagnostics.
- To improve the information available on sSMCs to reduce unwarranted pregnancy terminations.
Main Methods:
- Review of current state-of-the-art technologies applicable to sSMC characterization.
- Analysis of optimization strategies for sSMC detection in prenatal settings.
- Discussion of the clinical implications and diagnostic challenges associated with sSMCs.
Main Results:
- Conventional cytogenetics has limitations in fully characterizing sSMCs.
- Advanced technologies offer improved resolution and accuracy for sSMC identification.
- Optimized prenatal diagnostic approaches are crucial for accurate sSMC assessment.
Conclusions:
- Enhanced prenatal diagnostic strategies are essential for accurate sSMC detection.
- Improved characterization of sSMCs can lead to more informed clinical decisions.
- Providing reliable information on sSMCs is critical to prevent unnecessary pregnancy terminations.
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