The increased total cholesterol, leptin, and insulin with the normality of triglycerides in obese 18-day pregnant mares having nearly twice the body fat percent of their controls (47) disagree with the current results where obesity alone did not contribute to laminitis, hyperleptinemia, hyperinsulinemia, or increased total cholesterol, but hyperinsulinemia and hyperleptinemia may have contributed to the metabolic disorders in underconditioned or optimal-conditioned normal mares (7). The gene discussed is LEP; the disease is obesity due to melanocortin 4 receptor deficiency.