Quantitative measuring urinary glycosaminoglycan by dimethylmethylene-tris spectrophotometric method.

【Objective】 To set up a quantitative screening procedure for mucopolysaccharidosis(MPS) by measuring urinary glycosaminoglycan(GAG) based on 1,9-dimethylmethylene blue(DMB)-Tris assay. 【Methods】 The urinary GAG were detected by spectrophotometry and compared with that of appropriate standard solutions of heparan sulfate in 267 normal controls aged from neonates to adults,30 non-MPS patients and 12 patients with MPS diagnosed on the basis of clinical symptoms,abnormal urinary GAG electrophoresis and enzyme assay in leukocytes.The GAG was corrected for creatinine(Cr) content. 【Results】 The GAG concentrations were less than 70 mg/L in all normal controls and there was not significant relationship between the levels of GAG and ages.The ratios of GAG/Cr(mg/mmol) in normal controls were age-dependent from 39.1±13.0 in neonates to 3.9±1.6 in adults.Urinary GAG concentrations and GAG/Cr in patients with MPS were increased significantly compared to age-matched normal values except one patient with type IVA.Urinary GAGs excretions in all non-MPS patients were normal.The within-run CV and between-run CV were 1.3% and 3.6%,respectively. 【Conclusions】 This quantitative measurement of GAG based on DMB-Tris assay is a simple and reliable screening procedure for MPS.Normal reference values from a healthy population have been obtained and shown to be age dependent.