Iduronate Sulfatase, Fibroblasts
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Diagnosis of mucopolysaccharidosis II (MPS II, Hunter syndrome)
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Diagnostic testing for mucopolysaccharidosis II. Not recommended for carrier detection.
Additional Tests Lists test(s) that are always performed, at an additional charge, with the initial test(s)
|Test ID||Reporting Name||Available Separately||Always Performed|
|CRYOB||Cryopreserve for Biochem Studies||No||Yes|
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple lysosomal enzyme assays on a patient utilizing fibroblast culture, only 1 culture is required regardless of the number of enzyme assays ordered. If viable cells are not obtained within 10 days, client will be notified.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
IDNS/80945: Enzymatic/Radiolabeled/Anion Exchange Chromatography
CRYOB/88832: Fibroblast Subculture Followed by Cryopreservation and Storage
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Iduronate Sulfatase, Fibroblasts
Alpha-L-Idopyranosyluronic Acid 2-Sulfate Sulfahydrolase
Iduronate 2-Sulfatase Deficiency
Sulfoiduronate Sulfatase Deficiency
Iduronate 2-Sulfatase Deficiency
Sulfoiduronate Sulfatase Deficiency
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
This test is not recommended for prenatal testing.
Forms: New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.
Submit only 1 of the following specimens:
Specimen Type: Cultured fibroblasts
Container/Tube: T-75 or T-25 flask
Specimen Volume: 1 full T-75 flask or 2 full T-25 flasks
Specimen Stability Information: Ambient (preferred)/Refrigerated <24 hours
Specimen Type: Skin biopsy
Container/Tube: Sterile container with any standard cell culture media (eg, minimal essential media, RPMI 1640). The solution should be supplemented with 1% penicillin and streptomycin. Tubes can be supplied upon request (Eagle's minimum essential medium with 1% penicillin and streptomycin [Supply T115]).
Specimen Volume: 4-mm punch
Specimen Stability Information: Refrigerated (preferred)/Ambient
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Specimen in formalin or fixative preservative
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mucopolysaccharidosis II, (MPS II, Hunter syndrome) is an X-linked lysosomal storage disorder caused by the enzyme deficiency of iduronate sulfatase (IDS). The mucopolysaccharidoses are a group of disorders caused by the deficiency of any of the enzymes involved in the stepwise degradation of glycosaminoglycans (GAG). Accumulation of GAG (previously called mucopolysaccharides) in lysosomes interferes with normal functioning of cells, tissues, and organs.
Clinical features and severity of symptoms of MPS II are widely variable ranging from severe disease to an attenuated form, which generally presents at a later onset with a milder clinical presentation. In general, symptoms may include coarse facies, short stature, enlarged liver and spleen, hoarse voice, stiff joints, cardiac disease, and profound neurologic involvement leading to developmental delays and regression. Unlike MPS I (Hurler syndrome), corneal clouding is not typically present. Because MPS II is an X-linked disorder, it occurs almost exclusively in males with an estimated incidence of 1 in 100,000 male births (though symptomatic carrier females have been reported). Treatment options include hematopoietic stem cell transplantation and/or enzyme replacement therapy.
A diagnostic workup in an individual with MPS II typically demonstrates elevated levels of urinary GAG and increased amounts of both dermatan and heparan sulfate detected on thin-layer chromatography. Reduced or absent activity of IDS is diagnostic of MPS II; however, enzymatic testing is not reliable to detect carriers. Molecular sequence analysis of the IDS gene allows for detection of the disease-causing mutation in affected patients and subsequent carrier detection in female relatives. Currently, no clear genotype-phenotype correlations have been established.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Values near zero suggest mucopolysaccharidosis II.
Values above the reference range are not clinically significant.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
This test cannot reliably determine carrier status for mucopolysaccharidosis II (MPS II).
Documentation of normal enzymatic activity of at least 1 other sulfatase is critical, as low levels of iduronate sulfatase enzyme activity are seen in the disorder multiple sulfatase deficiency, which has a similar clinical presentation to MPS II.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Martin R, Beck M, Eng C, et al: Recognition and diagnosis of mucopolysaccharidosis II (Hunter syndrome). Pediatrics 2008;121(2):e377-86
2. Wraith JE, Scarpa M, Beck M, et al: Mucopolysaccharidosis type II (Hunter syndrome): a clinical review and recommendations for treatment in the era of enzyme replacement therapy. Eur J Pediatr 2008;167(3):266-277
3. Wasteson A, Neufeld EF: Iduronate sulfatase from human plasma. Meth Enzymol 1982;83:573-578
4. Enns GM, Steiner RD, Cowan TM: Lysosomal Disorders. In Pediatric Endocrinology and Inborn Errors of Metabolism. Edited by K Sarafoglou, GF Hoffmann, KS Roth, New York, McGraw-Hill Medical Division, 2009, pp 732
Method Description Describes how the test is performed and provides a method-specific reference
In this procedure, a tritiated disulfated disaccharide, O-(a-L-idopyranosyluronic acid 2-sulfate)-(1-4)-2,5-anhydro-D-H-mannitol-6-sulfate, is used as the substrate. The enzyme iduronate sulfatase (IDS) hydrolyzes the substrate to form inorganic sulfate and labeled monosulfated disaccharide. The monosulfated product is then separated from the disulfated substrate by anion exchange chromatography.(Wasteson A, Neufeld EF: Iduronate sulfatase from human plasma. Meth Enzymol 1982;83:573-578)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
30-60 days depending on growth rate
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
3 years - Check with the lab for availability
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
88240-Cryopreservation for biochemical studies
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
|Result ID||Reporting Name||LOINC Code|
|29714||Reason For Referral||42349-1|