Characterization of Constitutional Chromosome Abnormalities by Comparative Genomic Hybridization

Comparative genomic hybridization (CGH) is a molecular cytogenetic technique that can characterize excess and missing cytogenetic material often unrecognizable by G-banding, in a one step global screening procedure. The advantage of CGH over conventional fluorescence in situ hybridization (FISH) with whole chromosome paints (wcps) and multicolor FISH is its ability to identify not only the chromosome from which the additional unknown material was derived but also to map the region involved to specific bands on the source chromosome. Defining the origin of additional cytogenetic material by FISH with various probes is expensive and laborious as numerous wcps may be required until the source chromosome is identified. In addition, the number of available region specific probes is limited and covers only a fraction of the genome.