We recorded significant relationships between YKL-40 and leptin (r = −0.36, p = 0.031) as well as insignificant relationships with adiponectin (r = 0.05, p = 0.464) and resistin (r = −0.06, p = 0.198) in patients with JIA whose clinical condition had stabilized (inactive disease). The gene discussed is LEP; the disease is juvenile idiopathic arthritis.