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Test ID: GPSY Glucopsychosine, Blood Spot

Useful For

Quantification of glucopsychosine (glucosylsphingosine) in dried blood spots supports the biochemical diagnosis of Gaucher disease

 

May aid in monitoring a patient’s response to treatment

Reporting Name

Glucopsychosine, BS

Specimen Type

Whole blood


Specimen Required


Supplies: Card-Blood Spot Collection (Filter Paper) (T493) or Card-Postmortem Screening (Filter Paper) (T525)

Collection Container/Tube:

Preferred: Card-Blood Spot Collection (Filter Paper)

Acceptable: Whatman Protein Saver 903 filter paper, Ahlstrom 226 filter paper, Munktell filter paper, Card-Postmortem Screening (Filter Paper) (T525), or blood collected in tubes containing heparin or EDTA and dried on filter paper

Specimen Volume: 2 blood spots

Collection Instructions:

1. Completely fill at least 2 circles on the filter paper card (approximately 100 microliters blood per circle)

2. Let blood dry on filter paper at room temperature in a horizontal position for 3 or more hours.

3. Do not expose specimen to heat or direct sunlight.

4. Do not stack wet specimens.

5. Keep specimen dry.

Additional Information:

1. For collection instructions in Spanish, see Blood Spot Collection Card-Spanish Instructions (T777) in Special Instructions.

2. For collection instructions in Chinese, see Blood Spot Collection Card-Chinese Instructions (T800) in Special Instructions.


Specimen Minimum Volume

1 blood spot

Specimen Stability Information

Specimen Type Temperature Time
Whole blood Ambient (preferred) 96 days
  Frozen  96 days
  Refrigerated  96 days

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). Gaucher disease is caused by mutations 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, 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. Further 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/or 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) and molecular genetic analysis of the GBA gene (GAUP / Gaucher Disease, Mutation Analysis, GBA; or GBAZ / Gaucher Disease, Full Gene Analysis). Glucopsychosine is elevated in symptomatic patients and supports a diagnosis of Gaucher disease. It may also be helpful in determining treatment response.

Reference Values

Normal <47 nmol/L glucopsychosine

Interpretation

An elevation of glucopsychosine 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, 1993-2015. 2000 Jul 27 (Updated 2015 Feb 26). 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 Metabolic and Molecular Bases of Inherited Disease. Edited by D Valle, AL Beaudet, B Vogelstein, et al. New York, McGraw-Hill 2014, Accessed 08/11/2017. Avaliable at ommbid.mhmedical.com/content.aspx?bookid=971&sectionid=62643884

6. Murugeasan V, Chuan WL, Liu J, et al: Glucosylsphingosine is a key biomarker of Gaucher disease. Am J Hematol 2016;91(11)1082-1089

Day(s) and Time(s) Performed

Tuesday, Friday; 12 p.m.

Analytic Time

2 days

Test 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
GPSY Glucopsychosine, BS In Process

 

Result ID Test Result Name Result LOINC Value
62236 Glucopsychosine In Process
36344 Reviewed By No LOINC Needed
36345 Interpretation (GPSY) In Process

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Forms

1. 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 (T576) is available in Special Instructions.

2. Biochemical Genetics Patient Information (T602) in Special Instructions.

Testing Algorithm

See Newborn Screen Follow-up for Gaucher Disease in Special Instructions.

Mayo Medical Laboratories | Genetics and Pharmacogenomics Catalog Additional Information:

mml-biochemical