Optical genome mapping could change the existing workflow within cytogenetic laboratories Dutch-French research shows that Optical Genome Mapping (OGM) detects abnormalities in chromosomes and DNA very quickly, effectively and accurately. Sometimes even better than all existing techniques together, as they describe in two proof-of-concept studies published in the American Journal of Human Genetics. This new technique could radically change the existing workflow within cytogenetic laboratories. Human hereditary material is stored in 46 chromosomes (23 pairs). Although those chromosomes are quite stable, changes in number or structure can still occur. A well-known example is Down syndrome, which is caused by an extra chromosome 21 (trisomy 21). An extra chromosome makes a big difference and is quite easy to visualize. But all kinds of other, smaller changes can occur as well in chromosomes.