In pediatric ARDS (PARDS), we examined whether circulating heparan sulfate (HS) signatures, as readouts of eGCX shedding, capture inter-individual variability beyond other eGCX components and protein biomarkers, whether specific HS structural features are enriched, and whether they correlate with heparanase-1 (HPSE) activity. This evidence concerns the gene HPSE and pediatric acute respiratory distress syndrome.