No correlations were detected between serum leptin levels and glucose (p = 0.215), insulin (p = 0.988), age (p = 0.171), sex (p = 0.708), breed (p = 0.498), body weight (p = 0.976), or BCS (p = 0.720) in healthy dogs or in patients with cholelithiasis (p = 0.931, 0.638, 0.740, 0.968, 0.777, 0.920 and 0.541, respectively). The gene discussed is LEP; the disease is cholelithiasis.