Abnormal urinary excretion in sialoglycoconjugates in patients with mucopolysaccharidosis

Abnormal urinary excretion of sialoglycoconjugates was observed in four patients with mucopolysaccharidosis. Urinary sialoglycoconjugates were fractionated into 8 fractions by sequential gel filtration on Sephadex G-25, G-50 and by Dowex 1 ion-exchange chromatography. The comparison of the amounts of these fractions indicated that the fraction rich in mannose and glucosamine contents contributed to the increased urinary excretion of sialoglycoconjugates in patients with mucopolysaccharidosis. The major component of this fraction was disialyl-oroso-N-octaose which was a representative oligosaccharide side chain of glycoproteins with an Asn-GlcNAc linkage. Undoubtedly this abnormality is the secondary lesion of mucopolysaccharidosis, but it is conceivable that the disturbed metabolism of sialoglycoprotein is closely related to the pathogenesis of these diseases.