Normotensive dogs with MMVD stage B (median [interquartile range]: 1083.5 [574.8–1912.8] pmol/L) and hypertensive dogs with MMVD stage B (2345.0 [1812.5–2533.0] pmol/L) showed significantly higher NT-proBNP concentrations than dogs without MMVD (504 [430–774] pmol/L, p = 0.009 and p < 0.001, respectively), and dogs in the systemic hypertension group showed significantly higher NT-proBNP concentrations than those in the normotensive group (p = 0.046). The gene discussed is NPPB; the disease is Hypertension.