NPPA and hydrops fetalis: Pro-ANP is stored in secretory granules, mainly of cardiomyocytes, and cleaved into the 28 amino acid biologically active hormone (ANP) and the 98 amino acid N-terminal fragment (NT-proANP) by corin, a transmembrane serine protease, whose loss of function leads to a disease phenotype characterized by high BP with reduced ANP activity, in addition to contributing to the pathogenesis of HF [18,19].