Behnes M. et al. noticed that plasma levels of OPN were equivalent with echocardiographic left cardiac ventricular parameters and correlated positively with the functional New York Heart Association (NYHA) classification as well as with the structural classification of HF by the ACC/AHA classification in acute HF [30], furthermore emphasizing the overall biological importance of OPN in HF pathogenesis. The gene discussed is SPP1; the disease is hydrops fetalis.