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.

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

Method of Analysis: Dimethyl-methylene blue (DMB) Dye-Binding Spectrophotometry