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Updated: Jun 12, 2026
09:16
Array Comparative Genomic Hybridization (Array CGH) for Detection of Genomic Copy Number Variants
Published on: February 21, 2015
Additional cryptic CNVs in mentally retarded patients with apparently balanced karyotypes
Antoinet C J Gijsbers1, Cathy A J Bosch, Johannes G Dauwerse
1Center for Human and Clinical Genetics, Leiden University Medical Center (LUMC), Leiden, the Netherlands. a.c.j.gijsbers@lumc.nl
European Journal of Medical Genetics
|June 15, 2010
Summary
High-resolution whole-genome arrays detect submicroscopic abnormalities in apparently balanced chromosomal rearrangements linked to mental retardation (MR). This reveals additional copy number variants (CNVs) crucial for understanding complex karyotypes and MR phenotypes.
Area of Science:
- Genetics
- Medical Genetics
- Genomic Medicine
Background:
- Apparently balanced chromosome abnormalities are linked to mental retardation (MR).
- Conventional karyotyping has limitations in detecting small genomic abnormalities (<5-10 Mb).
- Submicroscopic abnormalities at breakpoints or elsewhere can cause MR phenotypes.
Purpose of the Study:
- To investigate submicroscopic genomic abnormalities in MR patients with balanced chromosomal rearrangements using whole-genome arrays.
- To determine the utility of high-resolution arrays in identifying copy number variants (CNVs) associated with MR phenotypes.
- To correlate complex karyotypes with MR phenotypes in affected individuals.
Main Methods:
- Whole-genome analysis using Single Nucleotide Polymorphism (SNP) arrays.
- Screening of 13 MR patients with previously identified balanced chromosomal abnormalities.
- Analysis of de novo, inherited, and unknown inheritance cases.
Main Results:
- All 13 MR patients exhibited abnormal phenotypes.
- Additional copy number variants (CNVs) were identified in 8 patients.
- CNVs were found adjacent to breakpoints and on unrelated chromosomes, indicating complex genomic alterations.
Conclusions:
- High-resolution array screening is essential for detecting submicroscopic abnormalities in MR patients with balanced chromosomal rearrangements.
- Combined array and conventional karyotyping approaches are necessary for accurate phenotyping of complex karyotypes.
- These findings highlight the importance of comprehensive genomic analysis in understanding the genetic basis of mental retardation.
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