Multisite Evaluation and Validation of Optical Genome Mapping for Prenatal Genetic Testing

Prenatal diagnostic testing of amniotic fluid, chorionic villi, or more rarely, fetal cord blood, is recommended following a positive or unreportable noninvasive cell-free fetal DNA test, abnormal maternal biochemical serum screen, abnormal ultrasound or increased genetic risk for a cytogenomic abnormality based on family history. While chromosomal microarray is recommended as the first-tier prenatal diagnostic test, in practice, multiple assays are often assessed in concert, to achieve a final diagnostic result. The use of multiple methodologies is costly, time consuming, and labor intensive. Optical genome mapping (OGM) is an emerging technique with application for prenatal diagnosis because of its ability to detect and resolve, in a single assay, all classes of pathogenic cytogenomic aberrations. In an effort to characterize the potential of OGM as a novel alternative to traditional standard of care (SOC) testing of prenatal samples, OGM was performed on a total of 200 samples representing 123 unique cases, which were previously tested with SOC methods (92/123 = 74.7% cases tested with at least 2 SOCs). OGM demonstrated an overall accuracy of 99.6% when compared with SOC methods, a positive predictive value of 100% and 100% reproducibility between sites, operators, and instruments. The standardized workflow, cost-effectiveness, and high resolution cytogenomic analysis demonstrates the potential of OGM to serve as a first-tier test for prenatal diagnosis.