Division of Human Genetics, The Children's Hospital of Philadelphia, and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA. shaikh@email.chop.edu
Genetic diseases arising from microdeletions and microduplications lead to copy number alterations of genomic regions containing one or more genes. Clinically, these rearrangements may be detected by routine cytogenetic testing, which may include karyotype analysis, subtelomeric analysis with fluorescence in situ hybridization, and/or fluorescence in situ hybridization directed at known chromosomal rearrangement-based disorders. The major limitations of these tests are low resolution and limited coverage of the genome. Array-based comparative genomic hybridization has recently become a widely used approach in the genome-wide analysis of copy number alterations in children with mental retardation and/or multiple congenital anomalies. Oligonucleotide-based arrays provide a genome-wide coverage at a much higher resolution than microarrays currently used in clinical diagnostics, greatly improving the rate of detection of submicroscopic copy number alterations in children with mental retardation and/or multiple congenital anomalies.
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