Thousands of Copy Number Variations Cataloged in New Genomic Database

A valuable new genomic database has been placed on the Internet, where it is freely available to gene researchers around the world.

The database, which catalogs and characterizes 54,462 individual DNA copy number variations (CNVs), was assembled by investigators at The Children's Hospital of Philadelphia (PA, USA). They analyzed blood samples taken from 2,026 disease-free individuals, using high-density, SNP-based oligonucleotide microarrays. The population studied was comprised mainly of Caucasians (65.2%) and African-Americans (34.2%). The samples were analyzed for CNVs in a single study using a uniform array platform and computational process.

Analysis of the data collected revealed that 77.8% of CNVs were from multiple unrelated individuals. These nonunique CNVs mapped to 3,272 distinct regions of genomic variation spanning 5.9% of the genome; 51.5% of these were previously unreported, and more than 85% were rare. On average the subjects in the study had approximately 27 CNVs each.

Results of the study were published in the July 10, 2009, online edition of the journal Genome Research, and the entire database was posted to The Children's Hospital of Philadelphia's website, where it is freely available in searchable form to gene researchers worldwide.

"This resource will be very important in enabling rapid and accurate diagnoses of rare diseases resulting from CNVs,” said first author Dr. Tamim H. Shaikh, assistant professor of pediatrics at The Children's Hospital of Philadelphia. "In order to pinpoint the one CNV that is the cause of a disease, it is critical to quickly eliminate those that are part of the spectrum of normal variation that exists in the human genome. That's what this CNV data and other similar resources allow us to do.”

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The Children's Hospital of Philadelphia