Successful optical genome mapping from 500 000 cells: A low-input UHMW DNA extraction approach

Optical Genome Mapping (OGM) is an emerging technology in clinical laboratories for identifying copy number and structural variations in the DNA of patients with haematological malignancies. A critical initial step is the isolation of ultra-high molecular weight genomic DNA (UHMW gDNA), which typically requires 1.5 million white blood cells. However, this cell number is not always achievable in clinical practice due to various limitations. For instance, diagnostic analysis of multiple myeloma (MM) is should be performed on CD138-positive cells derived from bone marrow aspirates (BMA), where both the sample volume and the number of CD138-positive cells This method describes a customized protocol which enables isolation of UHMW gDNA starting from as few as 500 000 cells, while still resulting in DNA of sufficient quality and quantity to perform OGM and collect at least 1500 Gbp of data.