Sly Syndrome (MPS VII): Urine Monitoring (Total GAGs, DS, CS)

Turnaround Time

14 days

CPT Code(s)

83864 x2

Cost

$300

• Sly Syndrome (MPS VII)

Sly syndrome, or mucopolysaccharidosis type VII, is a lysosomal storage disorder resulting from deficient enzyme activity of beta-glucuronidase. This autosomal recessive disorder has a highly variable phenotype. The most severe form presents prenatally as hydrops fetalis. Patients with a less severe phenotype present with hepatomegaly, skeleltal anomalies and coarse facies. The degree of cognitive impairment varies with the mildest cases surviving into adulthood.

For patients with an existing MPS diagnosis, measurement of glycosaminoglycans in urine can be used to monitor the effectiveness of treatments such as bone marrow translpant or enzyme replacement therapies.

Quantitative analysis of total glycosaminoglycans (GAGs) is performed using a 1,9-dimethylene blue (DMB) colorimetric reaction that is measured by spectrophotometry at a wavelength of 656 nm. GAG measurements are reported relative to the creatinine concentration in the patient's urine. Quantification of individual glycosaminoglycans -chondroitin sulfate (uCS), dermatan sulfate (uDS), heparan sulfate (uHS), and keratan sulfate (uKS)- is performed using liquid chromatography-tandem mass spectrometry.

At least 3 ml of a random catch sample of urine is needed for MPS urine monitoring.

Urine samples should be frozen after collection. Samples must be sent frozen via overnight delivery or courier, preferably on dry ice.