Abnormal urinary excretion of glycosaminoglycans in Albers-Schönberg disease.

Abnormal urinary excretion of acid mucopolysaccharides in two children affected with Albers-Schönberg disease is described. The urine specimens were first checked for their acid glycosaminoglycan (AGAG) content by a screening test. The AGAGs were then evaluated by uronic acid determination using the carbazole method, and the ratio between high molecular mass and low molecular mass AGAGs was determined. Qualitative characterization, before and after enzymatic digestion with chondroitinases AC (ChAC) and ABC (ChABC), of the total AGAGs contained in the specimen and of each AGAG separated with Dowex 1X2 was also performed by electrophoresis. The pattern of the urinary mucopolysaccharides in the two patients showed an abnormal quantity of heparan sulphate (HS) and a smaller quantity of dermatan sulphate (DS). Such abnormal urinary AGAGs excretion should confirm the assumption of some authors that malignant infantile osteopetrosis may be caused by a deficiency in the lysosomal enzymatic activity, or by some anomaly in the cell membrane function.