Test ID: G6ST
N-Acetylgalactosamine-6-Sulfate Sulfatase, Fibroblasts
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Assisting in the diagnosis of Morquio A disease
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
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 |
|---|---|---|---|
| FIBR | Fibroblast Culture | Yes | Yes |
| 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
Method Name A short description of the method used to perform the test
G6ST/80946: Enzymatic/Radiolabeled/Anion Exchange Chromatography
FIBR/8482: Cultivated from Biopsy as Monolayer
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
Aliases Lists additional common names for a test, as an aid in searching
Galactosamine-6-Sulfatate Sulfatase
Galactose-6-Sulfatase
Morquio A
Morquio A Disease
Morquio Syndrome
Morquio Syndrome A
Morquio Syndrome Type A
MPS 4A
MPS IVA
Mucopolysaccharidosis IV A
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.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | Specimen received 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.
| Specimen Type | Temperature | Time |
|---|---|---|
| Tissue | Varies | |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Mucopolysaccharidosis IVA, (MPS IVA, Morquio A syndrome) is an autosomal recessive lysosomal storage disorder caused by reduced or absent N-acetylgalactosamine-6-sulfate sulfatase (GALNS) enzyme activity. The mucopolysaccharidoses are a group of disorders caused by the deficiency of any of the enzymes involved in the stepwise degradation of dermatan sulfate, heparan sulfate, keratan sulfate, or chondroitin sulfate (glycosaminoglycans, GAGs). Accumulation of GAGs (previously called mucopolysaccharides) in lysosomes interferes with normal functioning of cells, tissues, and organs.
Clinical features and severity of symptoms of MPS IVA are widely variable, but may include skeletal dysplasia, short stature, dental anomalies, corneal clouding, respiratory insufficiency, and cardiac disease. Intelligence is usually normal. Estimates of the incidence of Morquio A syndrome range from 1 in 200,000 to 1 in 300,000 live births.
A diagnostic workup in an individual with MPS IVA typically demonstrates elevated levels of urinary GAGs and increased keratan sulfate and chondroitin-6-sulfate detected on thin-layer chromatography. Morquio B is a genetically distinct disorder caused by a deficiency of beta-galactosidase and has a significant number of overlapping clinical features with Morquio A. Enzyme analysis is necessary to distinguish between the 2 types. Reduced or absent activity of N-acetylgalactosamine-6-sulfate sulfatase enzyme in leukocytes and/or fibroblasts can confirm a diagnosis of MPS IVA. Sequencing of the GALNS gene allows for detection of disease-causing mutations in affected patients and identification of familial mutations allows for testing of at-risk family members.
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.
3.05-12.34 nmol/h/mg
Interpretation Provides information to assist in interpretation of the test results
Values <0.5 nmol/hour/mg confirms Morquio A disease.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The test cannot be used to establish carrier status for Morquio A disease.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Giugliani R, Harmatz P, Wraith JE: Management Guidelines for Mucopolysaccharidosis VI. Pediatrics 2007;120:405-418
2. 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
Morquio A disease (MPS IVA) results from a deficiency of the N-acetylgalactosamine-6-sulfate sulfatase enzyme. This enzyme hydrolyzes a sulfate group from the 6 position of galactose at the nonreducing terminus of the mucopolysaccharides, keratin sulfate and chondroitin-6 sulfate.
In this procedure, the tritiated disulfated trisaccharide, (6-DGalNAc-6-SO[4]) 1-4(beta-DGlcU)1-3 (D-[3]H GalNac-ol-6-SO[4]), is used as the substrate. The enzyme hydrolyzes the substrate to form inorganic sulfate and the labeled monosulfated trisaccharide. The monosulfated product is then separated from the disulfated substrate by anion exchange chromatography. The product is then quantitated by scintillation counting. (Glosse J, Kress H: A sensitive procedure for the diagnosis of N-acetylgalatosamine-6-sulfate sulfatase deficiency in classical Morquio's disease. Clin Chim Acta 1978;88:111-119)
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.
Varies
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.
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
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.
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.
82658-N-Acetylgalactosamine-6-sulfate sulfatase
88233-Fibroblast culture
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 |
|---|---|---|
| 29720 | Specimen | 31208-2 |
| 29721 | Specimen ID | N/A |
| 29722 | Source | N/A |
| 29723 | Order Date | N/A |
| 29724 | Reason For Referral | 42349-1 |
| 29725 | Method | In Process |
| 30052 | N-Acetylgalactosamine 6 Slft, Fibro | 2647-6 |
| 29726 | Interpretation | 59462-2 |
| 29727 | Amendment | In Process |
| 29728 | Reviewed By | N/A |
| 29729 | Release Date | N/A |
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