ECM secretory proteins fibulin 5 (FBLN5) and microfibril-associated protein 4 (MFAP4, RNA–protein-co-regulated) were upregulated in all HF conditions, most in ICM-DM, and were recently identified as HF-associated serum proteins independent of traditional risk factors suggesting plasma biomarkers of left ventricular origin (Dataset EV74) (Shah et al, 2024; Uhlén et al, 2019). Here, FBLN5 is linked to hydrops fetalis.