Iduronate-2-Sulfatase, Leukocytes

Casandra

Casandra Test Code MC76620Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID I2SWBCPT Code 82657

Iduronate-2-Sulfatase, Leukocytes

Clinical Use

Use

This test supports the biochemical diagnosis of mucopolysaccharidosis II (MPS II; Hunter syndrome) in whole blood specimens. MPS II is an X-linked lysosomal disorder caused by the deficiency of iduronate sufatase enzyme due to variants in the IDS gene. The clinical features and severity of symptoms vary widely, ranging from severe infantile onset disease to milder forms with later onset. Symptoms include coarse facies, short stature, enlarged organs, and neurologic involvement. Early diagnosis and treatment are desirable due to availability of therapies such as stem cell transplantation and enzyme replacement, which improve outcomes.

Special Instructions

For optimal isolation of leukocytes, it is recommended the specimen arrives refrigerated within 6 days of collection. Collect specimen Monday through Thursday only and not the day before a holiday. Patient's age and reason for testing are required. Informed consent is required for New York clients and must be documented on the request form.

Limitations

This test is not useful for carrier detection for MPS II. Pseudodeficiency alleles can show reduced enzyme activity. Enzyme levels may be normal in individuals receiving replacement therapy or transplants. Iduronate-2-sulfatase deficiency also occurs in multiple sulfatase deficiency, making enzyme testing unreliable for carrier detection. Additional biochemical or molecular testing is needed to confirm diagnosis.

Test Details

New York Approved