Taking these characteristics of leptin into account, several studies were conducted investigating serum leptin levels in BD patients.11,13,45,46 While Kavuncu et al.46 found no statistically significant difference in serum leptin levels between BD patients and healthy controls, in the other three studies it was reported that serum leptin levels of BD patients were elevated and that leptin may play a role in the pathogenesis of BD via endothelial function.11,13,45. This evidence concerns the gene LEP and Behcet disease.