Interpretive Handbook

Oligosaccharides (carbohydrate compounds) are routinely excreted in the urine. There is an increased accumulation of oligosaccharides in the urine of individuals with the any of the mucolipidoses and certain glycoprotein storage disorders. Glycoprotein storage disorders are caused by deficiencies of enzymes required for the degradation of oligosaccharide chains (see table below).

Oligosaccharidoses often clinically resemble mucopolysaccharidoses. Patient presentations range from almost normal to a variety of clinical symptoms which may include coarse facial features, bone and joint dysplasia, hepatosplenomegaly, and mental regression. Oligosaccharides are not detectable in all patients with oligosaccharidoses. Oligosaccharides are excreted in low levels in some disorders.Patients with alpha-mannosidosis, alpha-fucosidosis, and aspartylglucosaminuria may have very subtle excretions, where as patients with beta-mannosidosis, mucolipidosis II, and mucolipidosis III generally do not have detectable oligosaccharides in urine. In addition, a false-negative result can be observed when a urine specimen is particularly dilute. Pompe disease (a glycogen storage disease), Gaucher disease (a lysosomal storage disease), and Sandhoff disease (a sphingolipidosis) are other conditions which may yield a positive urine oligosaccharide result. Correlation of clinical presentation with oligosaccharide result and confirmatory testing is strongly recommended.

Excretion of Oligosaccharides in Oligosaccharidoses and Other Disorders

Screening for possible oligosaccharidoses

This is a screening test; not all oligosaccharidoses are detected. The resulting thin-layer chromatography pattern may be characteristic of a specific disorder; however, abnormal results require confirmation by enzyme assay.

When abnormal results are detected with characteristic patterns, a detailed interpretation is given, including an overview of results and significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing, and in vitro confirmatory studies (enzyme assay, molecular genetic analysis).

The test can give false-negative results, especially in older patients with mild clinical presentations. Patients with sialidosis or mucolipidosis II or III are not reliably detected.

In infants, many oligosaccharide bands are often detected and the clinical significance of the results may be uncertain. Retesting between the ages of 6 months to 1 year is recommended.

Enzyme analysis is required to confirm suspected diagnosis.

An interpretive report will be provided.

Beck M: Mucopolysaccharidoses and oligosaccharidoses. In Inborn Metabolic Diseases. Third edition. Edited by J Fernandes, JM Saudubray, G von den Berghe. Berlin, NY, Springer-Verlag, 2000, pp 413-421