Laboratory: Clinical Biochemistry  (METABOLIC)
Test Name:
MUCOPOLYSACCHARIDES SCREEN (MPS) - (U)
Test Code: MPS
Clinical Information:
Alternate Names: Urinary Glycosaminoglycans, GAGs Screen
 

Test Indications: Mucopolysaccharidoses (MPS) are rare genetic disorders characterized based on the resulting enzyme deficiency and pattern of GAG accumulation. These conditions are inherited in an autosomal-recessive manner, except for iduronate-2-sulfatase deficiency (MPS II), which is X-linked. The elevated concentration of total GAGs in various specimen types indicates a defect in their degradation and additional differentiation between GAGs (chondroitin sulfate [CS], dermatan sulfate [DS], heparan sulfate [HS], keratan sulfate [KS], and hyaluronan) can be diagnostic of a particular MPS or narrow the differential diagnosis. GAGs also accumulate in autosomal-recessive multiple sulfatase deficiency (MSD) and mucolipidoses II/III (MLII/III). 


The accumulation of mucopolysaccharides/glycosaminoglycans in various organs causes progressive multisystem disease, often involving organomegaly, skeletal abnormalities, “coarse” facial features and intellectual disabilities.

 

MPS screening by dimethylmethylene blue (DMB) dye-binding spectrophotometric assay represents the initial step in diagnosing most MPS disorders. 
 
Positive MPS screening results will be send out to a reference lab for confirmation by LC-MSMS. (see Mucopolysaccharide Fractionation - (U)).

If the DMB screen test is negative but there are a strong clinical suspicion of  a Mucopolysaccharidosis, please communicate with the biochemical geneticist.

This test is lab developed method performed by spectrophotometry at Metabolic Lab, HSC.
Collection Devices:
Specimen Required:
Urine: 10.0 mL
Pediatric Urine: 5.0 mL

Collection Information: Minimum volume: 1 mL if <1.0 mL, please call the Metabolic Lab, 204-787-4530.

Sample must be free of RBC and/or WBC.

Specimen Stability:

Ambient: 7 days

Refrigerated: 90 days (preferred)

Frozen: 1 year
Referral:
Urine: 10.0 mL
Pediatric Urine: 1.0 mL

Shipping & Storage: Freeze specimen immediately.

Send frozen specimen to Health Sciences Centre – MS5 (Biochemical Genetics)
Requisition:
Reference Values:
Age:                                         MPS (mg/mmol creat)
0 - 3 months                                    Less than 54
4 - 18 months                                  Less than 35
19 - 36 months                                Less than 21
37 - 84 months                                Less than 16
8 - 16 years                                     Less than 10
> 16 years                                       Less than 4

Historical results are reported (U/mmol creat.) 1 mg = 1 U

Method of Analysis: Dimethyl-methylene blue (DMB) Dye-Binding Spectrophotometry
 
Availability:
Routine
TAT: 1 month
See Also:
More Information:
Immediately freeze specimen
If you have any question, please communicate with the Metabolic Lab 204-787-4530.