While trials with pre-selection criteria, like New York Heart Association (NYHA) stage, amino-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels, and concomitant comorbidities, provide valuable information such as the efficacy of specific medical treatment of HF, they may also potentially limit the generalizability of the findings to the real-world clinical practice [15,16]. The gene discussed is NPPB; the disease is hydrops fetalis.