Rare Structural Variants Uncovered by Optical Genome Mapping in Multisystem Inflammatory Syndrome in Children (MIS-C)

Multisystem inflammatory syndrome in children (MIS-C) is a pediatric complication of SARS-CoV-2 infection characterized by multiorgan inflammation and frequently by cardiovascular dysfunction. In a single-center prospective cohort study, optical genome mapping (OGM) was performed on 14 patients, including 11 meeting CDC criteria for MIS-C and 3 with MIS-C-like (MIS-CL) presentations. SVs and CNVs were filtered against population and internal OGM control databases. Seven patients (50%) harbored prioritized variants within or near genes implicated in immune regulation or SARS-CoV-2 response. These included intronic insertions or deletions in ORAI1, STAT4, and ITPR1 (n = 4 patients); a heterozygous insertion disrupting BATF; a large deletion spanning exons 2-10 of CFHR5; and an upstream insertion near DOCK2. Application of OGM to patients with MIS-C and MIS-CL revealed SVs potentially impacting inflammation, COVID-19 severity, and Kawasaki Disease susceptibility. Although causality cannot yet be assigned, the identification of rare structural variants highlights biologically plausible mechanisms that may contribute to disease heterogeneity. These findings establish the feasibility and value of OGM in the assessment of complex pediatric syndromes, such as children with MIS-C or a severe course of SARS-CoV-2 infection.