Bionano Genomics, Inc. announced a publication covering the largest independent prospective prenatal study comparing optical genome mapping (OGM) to a combined workflow of chromosomal microarray analysis (CMA) and karyotyping (KT). The study highlighted OGM's high analytical concordance with the combined workflow of CMA and KT, and its ability to detect novel pathogenic structural variants (SVs) missed by those methods. The study also highlighted OGM's potential to provide additional information about SVs and copy number variants (CNVs) compared to CMA and KT.

The study, published by researchers from Nanjing Women and Children's Healthcare Hospital in China, reported that OGM demonstrated robust performance across multiple technical and analytical metrics when compared to CMA and KT. OGM also revealed the location and orientation of duplication segments, refined breakpoints of SVs and identified specific repeat contraction disorders that were not detected by other methods. Researchers used 200 unique prospective prenatal samples with soft markers (including increased nuchal translucency, nasal bone hypoplasia and mild ventriculomegaly, and structural anomalies) for the study.

Within this prospective cohort, OGM showed a 97.4% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 99.4% negative predictive value (NPV) for detecting SVs reported with KT and CMA. OGM identified several additional SVs not detected by CMA and KT and defined location and orientation for eight CNVs, which may help researchers interpret the effect of CNVs more precisely. OGM also detected 8 D4Z4 repeat contractions on the permissive 4qA haplotype that may indicate facioscapulohumeral muscular dystrophy type 1 (FSHD1).

The study authors concluded that OGM has the potential to serve as a first-tier cytogenetic method for prenatal analysis due to its ability to identify the majority of pathogenic SVs in a single assay.