Optical genome mapping validated
A new study validated Optical Genome Mapping (OGM) for detecting complex structural variants missed by exome sequencing, using a hybrid workflow with long‑read sequencing. The approach could expand genomic analyses available from cytology-derived nucleic acid when traditional exomes fall short. (x.com/OuterWebster/status/2038071497059655817)
npj Genomic Medicine published an open‑access study titled "Completely resolved structural variants by optical genome mapping with adaptive sampling from CNV discovery" by Li Fu et al., accepted 6 March 2026 and posted 26 March 2026. (nature.com) The authors applied optical genome mapping (OGM) to 30 cases that had copy‑number variants (16 deletions, 7 duplications, 7 mixed) originally flagged by exome sequencing, and OGM revealed additional structural variants in 14 of 30 cases (46.7%). (researchsquare.com) Targeted Oxford Nanopore long‑read sequencing with adaptive sampling was used to resolve OGM‑identified events to nucleotide breakpoints, and the hybrid workflow produced breakpoint‑level resolution that explained clinical features in 7 of 30 cases (23.3%). (researchsquare.com) (oxfordnanoporedx.com) The manuscript reports that OGM detected and fully resolved complex rearrangements involving multiple chromosomal segments and breakpoints that conventional exome analysis failed to reconstruct. (sciety.org) OGM workflows begin with isolation of ultra‑high molecular weight (UHMW) DNA (commonly >150 kb) and vendors publish validated extraction and labeling kits for blood, bone marrow, cultured cells, tissue and tumor biopsies for the Bionano Saphyr platform. (bionano.com 1) (bionano.com 2) Peer‑reviewed literature and lab‑validation resources confirm cytology preparations (cell blocks, touch imprints and cytology supernatants) can yield high‑quality DNA for NGS‑level assays, indicating existing cytology‑derived nucleic acid sources are documented as usable for molecular testing workflows in diagnostic labs. (colab.ws) (mdanderson.elsevierpure.com)
