Optical Genome Mapping Hailed as Next-Gen Cytogenetics

A new study has found that optical genome mapping (OGM) detects abnormalities in chromosomes and DNA very quickly, effectively, and accurately. According to the paper published in the American Journal of Human Genetics, this new technique could radically change the existing workflow within cytogenetic laboratories.

Cytogenetics is the genetic discipline that typically is used to examine chromosomes for abnormalities. To visualize both the large and small changes, several complementary techniques are needed, such as FISH, karyotyping, and copy number variant microarrays. These are often laborious techniques that individually can only visualize some of the abnormalities. The benefit of optical genome mapping is that it brings together all of these techniques.

Co-author of the paper Alexander Hoischen from Radboud University Medical Center highlights two major advantages of OGM: "We can now look at extremely long stretches of DNA, so there's fewer pieces needed to map the entire chromosome. It's faster and produces fewer errors. Furthermore, unlike the other techniques, we do not have to pre-process or manipulate the DNA, so we look at the real, 'natural' DNA. In short: what you see is what you get."

The team tested OGM on 85 samples from patients with a hereditary disorder that had previously been examined with the standard tests (karyotyping, FISH, CNV microarray). OGM found them all. A second team looked at the DNA of leukemia cells from 52 patients. Here too, OGM performed optimally by detecting all clinically known deviations. In addition, in a number of cases, the technique provided better and more accurate analyzes of chromosomal abnormalities.