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07:34
FISH for Pre-implantation Genetic Diagnosis
Published on: February 23, 2011
Redefining the risks of prenatally ascertained supernumerary marker chromosomes: a collaborative study
M D Graf1, L Christ, J T Mascarello
1Center for Human Genetics Laboratory and Department of Genetics, Case Western Reserve University, Cleveland, OH, USA.
Journal of Medical Genetics
|August 3, 2006
Summary
Prenatally detected de novo marker chromosomes carry a 26% risk of phenotypic abnormality. This risk decreases to 18% if high-resolution ultrasound studies are normal, highlighting the importance of further genetic evaluation.
Area of Science:
- Cytogenetics
- Prenatal Diagnosis
- Genetics
Background:
- Marker chromosomes are structurally abnormal chromosomes not identifiable by routine cytogenetics.
- Phenotypic abnormality risks depend on inheritance, ascertainment, origin, and marker characteristics.
Purpose of the Study:
- To understand the karyotype-phenotype relationship of prenatally ascertained supernumerary de novo marker chromosomes.
- To refine phenotypic risk estimates for these markers.
Main Methods:
- Combined data from 108 prenatal cases across 12 laboratories and literature studies.
- Analyzed cytogenetic and phenotypic data for supernumerary de novo marker chromosomes.
- Grouped risk estimates by marker type and ultrasound findings.
Main Results:
- A 26% risk of phenotypic abnormality for prenatally detected de novo supernumerary marker chromosomes without further information.
- Normal high-resolution ultrasound findings reduce this risk to 18%.
Conclusions:
- Additional genetic studies are crucial for precise risk assessment in marker chromosome cases.
- This study refines risk stratification for prenatal marker chromosome detection.
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