Moreover, leptin level was different between obese and non-obese women.32,33 In RA patients without any inflammatory disorders, leptin level correlated with BMI, although its levels were similar between patients and HCs.34,35 Deep brain stimulation (DBS) in the subthalamic nucleus (STN) caused weight gain in PD patients, but leptin levels did not change after surgery.36 These findings reinforce the hypotheses that leptin level alterations in some disorders such as PD associates with BMI and fat mass rather than disorder. This evidence concerns the gene LEP and Parkinson disease.