Authors' recommendations: Chromosome abnormalities are a significant cause of morbidity and mortality in fetuses, infants, and children. Conventional cytogenetics will identify a chromosome abnormality in up to 60% of firsttrimester miscarriages, 6% of stillbirths, and 0.6% of live-born infants. In addition, approximately 5% to 10% of prenatal samples will have an identifiable chromosome abnormality. Among individuals with developmental delay, intellectual disability, and/or congenital anomalies, approximately 10% will have abnormalities detectable by conventional karyotype analysis or fluorescence in situ hybridization (FISH). Comparative genomic hybridization (CGH) utilizing microarray technology has been used for several years in the clinical diagnosis of children and adults with a suspected genetic syndrome of unknown etiology. This technique involves comparing the genomes of two individuals:the patient and a normal control. Through hybridization to a microarray containing thousands of DNA segments (typically, bacterial artificial chromosome [BAC] clones or oligonucleotide probes), genomic imbalances such as deletions and duplications may be identified. Array-based CGH (aCGH) offers a cytogenetic evaluation at a significantly higher resolution than a standard karyotype analysis, as well as the ability to look for genomic imbalances throughout the genome in a single assay. The array may be targeted in nature, assaying certain regions of the genome known to be associated with a specific syndrome or phenotype, or may be genome wide. The arrays vary by the number, size, and distribution of the clones, or targets, used. The use of a large number of small clones (oligonucleotides) that are more closely spaced leads to an increased resolution. The mainissue with aCGH, particularly with the genome-wide arrays, is the identification of variants of unknown clinical significance. In addition, aCGH will not detect balanced rearrangements (i.e., balanced translocations or inversions), certain forms of polyploidy (addition of full haploid sets of chromosomes), or imbalances not covered by the clones on the array. The applications of aCGH in prenatal and pediatric populations include testing for aneuploidy and segmental imbalances, and evaluating unclear or apparently balanced rearrangements.

Project Status: Completed

Year Published: 2010

URL for published report: http://www.hayesinc.com/hayes/crd/?crd=8807

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: HAYES, Inc.

Contact Address: 157 S. Broad Street, Suite 200, Lansdale, PA 19446, USA. Tel: 215 855 0615; Fax: 215 855 5218

Contact Name: saleinfo@hayesinc.com

Contact Email: saleinfo@hayesinc.com

Copyright: 2010 Winifred S. Hayes, Inc