For instance, a patient with mild HF symptoms, elevated BNP, and preserved EF, along with diastolic dysfunction on echocardiography, might qualify as having HFpEF in the studies by Kresoja et al. and Rommel et al., but would be excluded by the studies conducted by Patel et al. and Zamani et al. The gene discussed is NPPB; the disease is hydrops fetalis.