Hunter Syndrome (MPS II): 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.

In addition, it can be used to clarify molecular findings in the IDS gene and to follow up abnormal newborn screening results.

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, leukocytes, cultured fibroblasts, or dried blood spots. For plasma and leukocytes, please send 5-10 ml of whole blood in a green top (sodium heparin) tube. Alternatively, plasma can be removed from spun 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. Plasma 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. Ship at ambient temperature.

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
Falecia Thomas, MS, CGC

Meet Ella

We will remember February 26th for the rest of our lives. On that day, we received the call from the Greenwood Genetic Center that they had discovered our daughter, Ella Marie, has Kleefstra syndrome. Very early on, my wife, Kelly, observed Ella being delayed in some of her milestones. Kelly monitored Ella’s progression and sought out testing in an effort to get Ella some assistance. Along the way, we were sent to GGC and met with LEARN MORE

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