FSTL3, an extracellular regulator of TGF-β family cytokines such as activin A, is involved in various biological functions including cell proliferation and inflammation, and altered transcriptomic regulation of the gene with another follistatin family member FSTL1 in myocardium has been associated with HF severity (30). The gene discussed is TGFB1; the disease is hydrops fetalis.