However, HF should be diagnosed for patients who are less than 50 years old with NT-proBNP levels > 450 pg/mL, patients who are between 50 and 75 years old with NT-proBNP levels > 900 pg/mL, and patients who are more than 75 years old with NT-proBNP levels > 1800 pg/mL [66]. The gene discussed is NPPB; the disease is hydrops fetalis.