Urinary glycosaminoglycan excretion in urolithiasis.

Urinary glycosaminoglycan (GAG) excretion was measured in children with idiopathic urolithiasis (15 girls and 10 boys; mean (SD) age 6.2 (2.4) years) and in healthy controls (10 girls and 14 boys; mean (SD) age 6.8 (3.8) years). GAG excretion was expressed as a GAG/creatinine (mg/g) ratio and was evaluated using dimethylmethylene blue. In healthy control children, the mean (SD) GAG/creatinine ratio was 31.67 (12.76) and it was similar in girls and boys. The children with idiopathic urolithiasis had significantly lower mean (SD) GAG/creatinine ratios than controls (22.59 (7.35)). Therefore, urinary GAG excretion may be important in the disease process in children with urolithiasis, as it is in adults.