Urinary Glycosaminoglycan Estimation as a Routine Clinical Service

Area of Science:

• Biochemistry
• Clinical Chemistry
• Genetics

Background:

• Mucopolysaccharidoses (MPS) are inherited metabolic disorders.
• Defects in glycosaminoglycan (GAG) metabolism cause MPS.
• Urinary GAG assessment is crucial for MPS screening.

Purpose of the Study:

• To optimize and validate a spectrophotometric quantitative method for urinary GAG.
• To establish age-matched normal ranges for urinary GAG.
• To assess the clinical utility of the method for MPS screening.

Main Methods:

• Optimization of a spectrophotometric method using dimethylmethylene blue dye.
• Quantification of GAG using heparan sulfate as standard.
• Determination of linearity (10-89 mg/L) and establishment of normal ranges in 177 healthy individuals across 8 age groups.
• Clinical validation using urine samples from 10 MPS patients.

Main Results:

• The optimized method demonstrated linearity and robustness.
• Significant variations in urinary GAG concentrations were observed across different age groups, with neonates having higher levels than adults.
• The method showed high accuracy in distinguishing MPS patients from healthy individuals.

Conclusions:

• The developed spectrophotometric method is a simple, robust, and validated screening tool for mucopolysaccharidoses.
• This assay is suitable for routine implementation in clinical chemistry laboratories.
• Accurate GAG quantification aids in early diagnosis and management of MPS.