Supporting the biochemical diagnosis of multiple sulfatase deficiency in whole blood specimens
This test is not useful for carrier detection.
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
GALNS
Galactosamine-6-sulfate sulfatase
GNS
Heparan-N-sulfatase
Heparan sulfate sulfatase
I2S
Multiple Sulfatase deficiency
MSD
Iduronate-2-sulfatase
N-acetylgalactosamine-6-sulfatase
N-acetylglucosamine-6-sulfatase
SGSH
SUMF1
Whole Blood ACD
For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerated within 6 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.
1. Patient's age is required.
2. Reason for testing is required.
Question ID | Description | Answers |
---|---|---|
BG771 | Reason for Referral |
Rule out MSD Follow up of known MSD Not Provided |
Container/Tube:
Preferred: Yellow top (ACD solution B)
Acceptable: Yellow top (ACD solution A) or lavender top (EDTA)
Specimen Volume: 6 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
5 mL
Gross hemolysis | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood ACD | Refrigerated (preferred) | 6 days | |
Ambient | 6 days |
Supporting the biochemical diagnosis of multiple sulfatase deficiency in whole blood specimens
This test is not useful for carrier detection.
Multiple sulfatase deficiency (MSD) is a rare autosomal recessive lysosomal disorder caused by mutations in the sulfatase-modifying factor 1 (SUMF1) gene. SUMF1 encodes for a formylglycine-generating enzyme that performs a critical posttranslational modification necessary for activation of all human sulfatases, including arylsulfatase A and B. The clinical features of MSD encompass symptoms of every single sulfatase deficiency, including metachromatic leukodystrophy (MLD), the mucopolysaccharidoses, X-linked ichthyosis, and chondrodysplasia punctata type I. Age of onset and clinical severity are variable and correspond with the level of residual enzyme activity. A severe neonatal form of MSD closely overlaps the clinical presentation of the mucopolysaccharidoses, but it is often fatal within 1 year. Late-infantile MSD (onset 0-2 years) accounts for most cases and is characterized by a clinical presentation similar to MLD.
A diagnostic workup for MSD demonstrates reduced enzyme activity of several sulfatase enzymes including those on this panel (iduronate-2-sulfatase, heparan sulfate sulfatase, galactosamine-6-sulfate sulfatase, and arylsulfatase B). Individuals with MSD typically have an increased urinary excretion of sulfatides as well as increased urinary glycosaminoglycans, therefore a combined analysis of urine ceramide trihexoside, mucopolysaccharides, oligosaccharides, and sulfatides (LSDS/ Lysosomal Storage Disorders Screen, Random, Urine) may support a diagnosis. Molecular genetic analysis of the SUMF1 gene (CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies; specify Gene List ID: IEMCP-PCUBX1) allows for detection of disease-causing variants in affected patients and subsequent carrier detection in relatives.
Iduronate-2-sulfatase: >2.20 nmol/hour/mg protein
Heparan-N-sulfatase: >0.13 nmol/hour/mg protein
N-acetylglucosamine-6-sulfatase: >0.03 nmol/hour/mg protein
N-acetylgalactosamine-6-sulfatase: >1.60 nmol/hour/mg protein
An interpretive report will be provided.
Abnormal results are not sufficient to establish a diagnosis of a particular disease. To verify a preliminary diagnosis based on this assay, additional biochemical or molecular genetic analyses are required.
When abnormal results are detected, a detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing, and in vitro, confirmatory studies (enzyme assay, molecular analysis), a phone number to reach one of the laboratory directors in case the referring physician has additional questions.
Individuals with pseudodeficiency alleles can show reduced enzyme activity.
Carrier status (heterozygosity) cannot be reliably detected.
1. Neufeld EF, Muenzer J. The mucopolysaccharidoses. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; Accessed July 14, 2023. https://ommbid.mhmedical.com/content.aspx?bookid=2709§ionid=225544161
2. Hopwood JJ, Ballabio A. Multiple sulfatase deficiency and the nature of the sulfatase family. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA. eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; Accessed July 14, 2023. https://ommbid.mhmedical.com/content.aspx?bookid=2709§ionid=225546905
Leukocytes are incubated with four cocktail mixes: 1) substrate and internal standard (IS) for iduronate 2-sulfatase, heparan N-sulfatase, alpha-N-acetylglucosaminidase, N-acetylgalactosamine-sulfate, beta-galactosidase, arylsulfatase B, beta-glucuronidase, and tripeptidyl peptidase 1; 2) substrate and IS for acetyl-CoA:alpha-glucosaminide N-acetyltransferase; 3) substrate and IS for N-acetylglucosamine-6-sulfatase ; and 4) substrate and IS for palmitoyl-protein thioesterase 1 in 96-well plates. Following overnight incubation, the plates are combined and purified by liquid-liquid extraction. The extracts are evaporated, reconstituted with mobile phase, and analyzed by tandem mass spectrometry.(Unpublished Mayo method)
Preanalytical processing: Monday through Saturday
Testing performed: Tuesday
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
82657
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
MSDW | Multiple sulfatase deficiency, WBC | 104073-2 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
BG771 | Reason for Referral | 42349-1 |
618466 | Iduronate-2-sulfatase | 24089-5 |
618467 | Heparan-N-sulfatase | 24086-1 |
620156 | N-acetylglucosamine-6-sulfatase | 24098-6 |
618468 | N-acetylgalactosamine-6-sulfatase | 24096-0 |
618469 | Interpretation | 59462-2 |
618465 | Reviewed By | 18771-6 |
Change Type | Effective Date |
---|---|
New Test | 2023-10-17 |