Urinary glycosaminoglycan excretion in healthy subjects and in patients with mucopolysaccharidoses

Abstract

Background: The mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by deficiency of enzymes catalyzing the stepwise degradation of glycosaminoglycans (GAGs), and are transmitted in an autosomal recessive manner, except for Hunter syndrome.

Methods: The levels of GAGs in 150 healthy subjects and 33 patients with MPS were determined, and results were expressed as milligrams of GAGs per grams of creatinine.

Results: We found that this ratio decreased with age during the first 15 years of life, but had a constant low rate between the ages of 17-40 years in healthy individuals. A different tendency was present in patients with MPS, because levels of GAG excretion in this group were higher (by four standard deviations up) compared with healthy individuals. The electrophoretic patterns of urinary GAGs in healthy subjects showed that the higher levels detected in urine were chondroitin sulfate (4 and 6) and a smaller quantity of dermatan sulfate, but in each MPS type its characteristic pattern was identified.

Conclusions: This is a simple, reproducible method suitable for routine laboratory separation, identification, and quantity of urinary GAGs and for diagnosing MPS syndromes.