A significantly lower PON1 activity (Fig. 4) was found in dogs with Stage D of CHF (median/25th–75th percentiles: 1.9/1.4–2.3 IU/L) compared with stage A dogs (median/25th–75th percentiles: 3.9/3.5–4.6 IU/L, P < 0.05) and with dogs with stage B2 (median/25th–75th percentiles: 3.9/3.5–4.3 IU/L, P < 0.05). The gene discussed is PON1; the disease is congestive heart failure.