Hunter Syndrome (MPS II): Iduronate-2-Sulfatase Enzyme Analysis

Turnaround Time

14 days

CPT Code(s)

82657

Cost

$200

Enzymes

• Hunter Syndrome (MPS II)

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.

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

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

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.

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.