Mucopolysaccharides and Oligosaccharides
|Clinical Use:||To screen for inborn errors of metabolism characterised by specific enzyme deficiency and pathological increase in mucopolysaccharide/ oligosaccharide concentrations in the urine.|
|Background:||Mucopolysaccharides:- Undegraded or partially degraded GAGs (also called mucopolysaccharides) are stored in lysosomes and are excreted in the urine. Accumulation of GAGs in lysosomes interferes with normal functioning of cells, tissues, and organs resulting in the clinical features observed in MPS disorders. There are 11 known enzyme deficiencies that result in MPSs.An inherited deficiency of any of the lysosomal enzymes involved in mucopolysaccharide degradation leads to abnormal intracellular storage of mucopolysaccharides, and also their abnormal excretion in urine.
Diseases in this group include Hurler, Scheie, Hunter, Sanfilippo, Morquio, Maroteaux-Lamy and Sly syndromes. MPSs are autosomal recessive disorders with the exception of MPS II, which follows an X-linked inheritance pattern. Affected individuals typically experience a period of normal growth and development followed by progressive disease involvement encompassing multiple systems. The severity and features vary, and may include facial coarsening, organomegaly, skeletal changes, cardiac abnormalities, and developmental delays. Disease presentation varies from as early as late infancy to adulthood.
Oligosaccharides:- 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.
Oligosaccharidoses clinically resemble mucopolysaccharidoses, varying from coarse facial features, bone and joint dysplasia, hepatosplenomegaly, and mental regression to an almost normal phenotype. Not all oligosaccharidoses have detectable oligosacchariduria. Successful detection of oligosaccharidoses depends on the amount of oligosaccharides excreted in the urine. Patients with alpha-mannosidosis, alpha-fucosidosis, and aspartylglucosaminuria may have very subtle excretions. Specimens from patients with beta-mannosidosis, mucolipidosis II, and mucolipidosis III, generally do not contain oligosaccharides in urine. Urinary oligosaccharides may also be detected in Pompe disease (a glycogen storage disease), as well as Gaucher and Sandhoff diseases (sphingolipidoses). Clinical correlation is strongly recommended.
|Patient Preparation:||None required|
|Specimen Requirements:||Random Urine – Collected into a plain universal|
|Turnaround Time:||3 weeks|
|Referred Test:||Referred test|