The diagnostic and prognostic roles of B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) are well established; however, an unmet need persists in accurately distinguishing HFpEF from HFrEF, as NT-proBNP levels are often influenced by age, renal function, and obesity, which confound its interpretation in HFpEF. The gene discussed is NPPB; the disease is obesity due to melanocortin 4 receptor deficiency.