Insights
Copy Number Variant (CNV) Detection at Blueprint Genetics
Sep 16, 2019

Blueprint Genetics offers high resolution CNV detection. CNV analysis is a powerful diagnostic tool, especially when paired with deep, uniform sequencing.

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What are CNVs?

  • A CNV is a type of genetic variant where there is either
    an extra or missing copy of a stretch of DNA.
  • CNVs can also be called deletions or duplications.
  • CNVs can range in size from small (several hundred base
    pairs) to very large (one million base pairs or more).

Why are CNVs important?

  • CNVs are becoming increasingly recognized as an
    important cause of many genetic diseases.
  • On average, 5-10% of disease-causing variants are CNVs.
    This number can be as high as 35% in some specialties
    (Truty et al, 2018).
  • Small CNVs (<3 exons) are the hardest to detect, but
    account for a significant portion of all CNVs (43% based
    on internal statistics).
  • Including high-resolution CNV detection provides a more
    comprehensive analysis than sequencing alone and
    maximizes the diagnostic potential for your patient.

Can next generation sequencing (NGS) reliably detect CNVs?

It has long been thought that NGS technologies are unable to detect small CNVs (ex. <3 exons) or very large CNVs (ex. microdeletion or microduplication syndromes).
However, our experience and analytic validation demonstrate that NGS can accurately detect both small and very large CNVs.

These factors include:

  • Good sample quality
  • Deep and uniform sequencing coverage
  • Multiple bioinformatic tools
  • Visualization of data and manual review for called CNV events to minimize false positives
  • The use of orthogonal confirmation techniques and policies