Mucopolysaccharidosis II (MPS II), Hunter Syndrome : iduronate-2-sulfatase enzyme analysis

Test Information

This biochemical test is a quantitative measurement of iduronate-2-sulfatase enzyme activity and can be used as a 1st tier test for patients with a clinical suspicion of Mucopolysaccharidosis II (MPS II), Hunter Syndrome. Demonstration of deficient iduronate-2-sulfatase enzyme activity is considered the gold standard to confirm a diagnosis of Mucopolysaccharidosis II (MPS II), Hunter Syndrome.

Turnaround Time

14 days

CPT Code(s)

82657

Cost

$200


Enzymes

iduronate-2-sulfatase

Clinical Information

Hunter syndrome is an X-linked lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase. Features include coarse facial appearance, short stature, hepatosplenomegaly, intellectual disability and joint stiffness. Typically, the disorder is diagnosed by enzymatic assay, however, the determination of carrier status using enzyme assay has proved problematic.

Indications

This test can be used to confirm a suspected Hunter syndrome diagnosis. Prenatal diagnosis and carrier testing via enzyme analysis are not available.

Methodology

Quantifies level of Iduronate-2-sulfatase via the 4-methylumbelliferyl substrate

Specimen Requirements

Enzyme activity can be measured in plasma, cultured fibroblasts, or dried blood spots. For plasma, please send 5-10 ml of whole blood in a green top (sodium heparin) tube OR plasma can removed from spun down sample and sent frozen.



For dried blood spot collection, a minimum of three circles need to be filled in. Each circle should contain one drop of blood (about 100 microliters). See the link below for additional sample collection and handling instructions.



In addition, a dried blood spot or blood drawn in an EDTA tube can be used for Hunter syndrome molecular analysis and may be sent for DNA banking. Please indicate on the requisition if DNA should be banked for follow-up molecular testing.

Transport Instructions

Whole blood should be sent over overnight at ambient temperature. Plamsa can be removed once the sample has been drawn and sent frozen on dry ice. Do not freeze whole blood.



Cultured fibroblasts can be sent overnight at room temperature.



For a dried blood spot: When the sample has dried 3-4 hours, fold cover at score line, over sample, and tuck into flap. Samples should be placed in the mail within 24 hours of collection. Overnight shipping is preferred.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Biochemical Testing, Individual Enzyme Assays
Lucy's Story

Lucy's Story

When our daughter Lucy had a metabolic crisis at 7 days old, we were shocked and devastated to find out that she was born with a rare genetic disorder (MSUD). Her newborn screening results did not make it back in time to prevent the crisis, and no one at our local hospital was familiar with the disease. They did not know how to treat her. Calls were made to Greenwood Genetic Center to confirm her diagnosis...

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