The results of our work, demonstrating the antifibrotic effects of relaxin-2, especially the ability to interfere with TGF-β1 signalling and to reduce fibroblast recruitment and activation, may help to provide useful data to investigate some future opportunities for the therapeutic use of relaxin-2 in fibrotic diseases, as HF and/or AF. The gene discussed is RLN2; the disease is hydrops fetalis.