Test ID GPSYW Glucopsychosine, Blood
Specimen Required
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin, lithium heparin) or yellow top (ACD B)
Specimen Volume: 1 mL
Forms
1. Biochemical Genetics Patient Information (T602) in Special Instructions.
2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.
Useful For
Second-tier test when newborn screening results with reduced beta-glucosidase (GBA) activity are identified
Diagnosis and monitoring of patients with Gaucher disease
Documentation of an elevated glucopsychosine (glucosylsphingosine: lyso-GL1) level supports the biochemical diagnosis of Gaucher disease
Monitoring a patient's response to treatment
This test is not useful for identifying carriers of GBA variants.
Special Instructions
Method Name
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Glucopsychosine, BSpecimen Type
Whole bloodSpecimen Minimum Volume
0.25 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole blood | Refrigerated (preferred) | 72 hours | |
Ambient | 48 hours |
Clinical Information
Gaucher disease is an autosomal recessive lysosomal storage disorder caused by a deficiency of the enzyme, beta-glucosidase. Beta-glucosidase facilitates the lysosomal degradation of glucosylceramide (glucocerebroside) and glucopsychosine (glucosylsphingosine: lyso-GL1). Gaucher disease is caused by variants in the GBA gene. There are 3 described types of Gaucher disease with varying clinical presentations and age of onset from a perinatal lethal disorder to an asymptomatic type. Features of all types of Gaucher disease include hepatosplenomegaly and hematological abnormalities.
Gaucher disease type I is the most common form, representing more than 90% of cases. It is generally characterized by bone disease, hepatosplenomegaly, anemia and thrombocytopenia, coagulation abnormalities, lung disease, but no central nervous system (CNS) involvement. Gaucher disease types II and III are characterized by the presence of primary neurologic disease. In addition, Type II typically presents with limited psychomotor development, hepatosplenomegaly, and lung disease, resulting in death usually between 2 and 4 years of age. Individuals with Gaucher disease type III may present prior to 2 years of age, but the progression is not as rapid and patients may survive into the third and fourth decade. Additional subtypes of Gaucher disease include a perinatal lethal form associated with skin abnormalities and nonimmune hydrops fetalis, and a cardiovascular form presenting with calcification of the aortic and mitral valves, mild splenomegaly, corneal opacities, and gaze impairment.
Treatment is available in the form of enzyme replacement therapy and substrate reduction therapy for types I and III. These treatment options have generally made bone marrow transplantation obsolete. Currently, only supportive therapy is available for type II because of the inability of enzyme provided by replacement therapy to cross the blood-brain barrier.
The incidence of Gaucher disease type I ranges from 1 in 30,000 to 1 in 100,000 in the general population, but is much more frequent among Ashkenazi Jews with an incidence of approximately 1 in 900. Types II and III both have an incidence of approximately 1 in 100,000 in the general population.
A diagnostic workup for Gaucher disease may demonstrate the characteristic finding of Gaucher cells on bone marrow examination, other hematologic abnormalities, and hepatosplenomegaly. The diagnosis can be confirmed by the demonstration of reduced or absent acid beta-glucosidase activity in leukocytes (BGL / Beta-Glucosidase, Leukocytes), or dried blood spots (PLSD / Lysosomal and Peroxisomal Storage Disorders Screen, Blood Spot) and molecular genetic analysis of the GBA gene (GAUP / Gaucher Disease, Mutation Analysis, GBA, Varies; or GBAZ / Gaucher Disease, Full Gene Analysis, Varies). Lyso-GL1 is elevated in symptomatic patients and supports a diagnosis of Gaucher disease. It may also be helpful in determining treatment response.
Reference Values
Cutoff: ≤0.040 nmol/mL
Interpretation
An elevation of glucopsychosine (glucosylsphingosine: lyso-GL1) is indicative of Gaucher disease.
Clinical Reference
1. Orvisky E, Park J, LaMarca M, et al: Glucosylsphingosine accumulation in tissues from patients with Gaucher disease: correlation with phenotype and genotype. Mol Genet Metab 2002;76:262-270
2. Pastores GM, Hughes DA: Gaucher Disease. In GeneReviews Edited by RA Pagon, MP Adam, HH Ardinger, et al: University of Washington, Seattle, 1993-2019. 2000 Jul 27 (Updated 2018 Jun 21). Accessed May 2019. Available at www.ncbi.nlm.nih.gov/books/NBK1269/
3. Dekker N, Dussen L, Hollak C, et al: Elevated plasma glucosylsphingosine in Gaucher disease: relation to phenotype, storage cell markers, and therapeutic response. Blood 2011;118(16):118-127
4. Kaplan P, Baris H, De Meirleir L, et al: Revised recommendations for the management of Gaucher disease in children. Eur J Pediatr 2013;172:447-458
5. Grabowski GA, Petsko GA, Kolodny EH, et al: Gaucher disease. In The Online Matabolic and Molecular Bases of Inherited Disease. Edited by D Valle, AL Beaudet, B Vogelstein, et al. New York, McGraw-Hill. Accessed August 11, 2017. Available at http://ommbid.mhmedical.com/content.aspx?bookid=971§ionid=62643884
6. Murugeasan V, Chuan WL, Liu J, et al: Glycosylsphingosine is a key biomarker of Gaucher disease. Am J Hematol 2016;91(11)1082-1089
Day(s) and Time(s) Performed
Samples received Monday through Saturday; 4 p.m.; Sunday 1 p.m. will be prepared same day.
Testing performed Tuesday; 8 a.m
Analytic Time
2 daysTest Classification
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
82542
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
GPSYW | Glucopsychosine, B | 92751-7 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
BA4357 | Interpretation (GPSYW) | 59462-2 |
BA4356 | Glucopsychosine | 92751-7 |
BA4358 | Reviewed By | 18771-6 |
Testing Algorithm
The following are available in Special Instructions:
-Newborn Screen Follow-up for Gaucher Disease
-Newborn Screening Act Sheet Gaucher Disease: Decreased Acid Beta-Glucosidase
mcl-newborn