Copy number variation (CNV) refers to structural alterations in the genome that result in the duplication or deletion of large segments of DNA, typically spanning thousands to millions of base pairs. CNVs can affect gene dosage, leading to changes in gene expression and contributing to various diseases, such as cancer, developmental disorders, and neurological conditions. Detecting CNVs is crucial for understanding genetic diversity and disease mechanisms. CNVs are represented in specialized fields within VCF files or separate file formats and require dedicated computational tools for accurate identification and analysis.