Copy-number variation

Copy-number variations (CNVs) are a form of structural variation that manifest as deletions or duplications in the genome. For example, the chromosome that normally has sections in order as A-B-C-D might instead have sections A-B-C-C-D (a duplication of "C") or A-B-D (a deletion of "C"). Cells with CNVs have abnormal or, for certain genes, normal variations in their copy number.