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.

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. 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
Meet Jeremiah

Meet Jeremiah

Play peek-a-boo with 9 month-old Jeremiah Licorish of Florence, and you'll be rewarded with a huge grin that lights up both his and his mother's faces. But this family has been through the unthinkable over the past few months, with very few reasons to smile. At first things were going well. Jeremiah was a happy, healthy newborn, doted on by his mother, Aneesa, and his three big brothers. But when Jeremiah was around 5 months old, Aneesa noticed changes in her youngest son's development...

In The News