Symptoms of congestive HF are usually mild in patients with ES due to right ventriclecompensation and adaptation through the years.14,33 Nevertheless, signs andsymptoms of HF, that usually develop in later stages of the disease, are associatedwith increased mortality in ES patients as well as older age.34,35 Hypoxia is oneof the most important factors determining the increase of BNP in unrepairedCHD.36,37 Therefore,more complex CHD could lead to more severe desaturation and increase in BNP amongpatients with ES, as it was observed in our study. The gene discussed is NPPB; the disease is hydrops fetalis.