Correlations were also revealed between urinary CS/DS and serum CRP levels in both healthy children from the control group (r = 0.6417; p = 0.0001) and in the patients with JIA from the following groups: TP (r = −0.5821; p = 0.00000), TR (r = 0.7821; p = 0.00001), T0 (r = −0.6508; p = 0.00002), and T24 (r = 0.7611; p = 0.00000). The gene discussed is CRP; the disease is juvenile idiopathic arthritis.