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Test ID: BGL Beta-Glucosidase, Leukocytes

Reporting Name

Beta-Glucosidase, Leukocytes

Useful For

Diagnosis of Gaucher disease

Specimen Type

Whole Blood ACD


Advisory Information


Preferred specimen for diagnostic testing. Not recommended for carrier detection; instead order GAUP / Gaucher Disease, Mutation Analysis, GBA.



Shipping Instructions


For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerated within 96 hours of draw to be stabilized. Draw specimen Monday through Thursday only and not the day before a holiday. Specimen should be drawn and packaged as close to shipping time as possible.



Specimen Required


Container/Tube:

Preferred: Yellow top (ACD solution B)

Acceptable: Yellow top (ACD solution A)

Specimen Volume: 6 mL

Collection Instructions: Do not transfer blood to other containers.


Specimen Minimum Volume

5 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood ACD Refrigerated (preferred) 4 days
  Ambient  48 hours

Reference Values

≥8.7 nmol/h/mg protein

Note: Results from this assay do not reflect carrier status because of individual variation of beta-glucosidase enzyme levels. For carrier testing, order molecular test GAUP / Gaucher Disease, Mutation Analysis, GBA.

Day(s) and Time(s) Performed

Specimens are processed Monday through Sunday.

Assay is performed on Monday.

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

82657

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BGL Beta-Glucosidase, Leukocytes In Process

 

Result ID Test Result Name Result LOINC Value
35636 Beta-Glucosidase, Leukocytes 32540-7
35637 Interpretation (BGL) 59462-2
35638 Reviewed By No LOINC Needed

Clinical Information

Gaucher disease is an autosomal recessive lysosomal storage disorder caused by reduced or absent acid beta-glucosidase (glucocerebrosidase) enzyme activity. Absent or reduced activity of this enzyme results in accumulation of glucocerebroside in the lysosomes and interferes with the normal functioning of cells.

 

Clinical features and severity of symptoms are widely variable within Gaucher disease, but in general, the disorder is characterized by abnormal blood parameters such as decreased red blood cells (anemia) and/or platelets (thrombocytopenia), bone disease, and hepatosplenomegaly. Individuals with more severe types of Gaucher disease may have central nervous system (CNS) involvement. There are 3 clinical subtypes of the disorder that vary with respect to age of onset and clinical presentation. Type 1 is the most common type, representing 95% of all cases, and is generally characterized by bone disease, hepatosplenomegaly, anemia and thrombocytopenia, coagulation abnormalities, lung disease, and no CNS involvement. Type 2 typically has a very severe progression with onset in the first 2 years of life including neurologic disease, hepatosplenomegaly, and lung disease, with death usually between 2 and 4 years due to lung failure. Individuals with type 3 may have onset prior to 2 years of age, but the progression is not as severe and they may survive into the third and fourth decade. Finally, there is 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, and corneal opacities.

 

Treatment is available in the form of enzyme replacement therapy, substrate reduction therapy, and/or chaperone therapy for types 1 and 3. Individuals with type 3 may benefit from bone marrow transplantation. Currently, only supportive therapy is available for type 2.

 

The incidence of type 1 ranges from 1 in 20,000 to 200,000 in the general population, but is much more frequent among Ashkenazi Jews with an incidence between 1 in 400 and 900. Types 2 and 3 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. Significantly reduced or absent enzyme activity of acid beta-glucosidase is diagnostic. Additionally, the biomarker, glucopsychosine is elevated in symptomatic patients and supports a diagnosis of Gaucher disease (GPSY / Glucopsychosine, Blood Spot). A targeted mutation panel may allow for detection of disease-causing mutations in affected patients (GAUP / Gaucher Disease, Mutation Analysis, GBA). In addition, full sequencing of the GBA gene allows for detection of disease-causing mutations in affected patients in whom a targeted mutation panel identifies no mutations or only a single mutation (GBAZ / Gaucher Disease, Full Gene Analysis).

Interpretation

Individuals affected with Gaucher disease will have enzyme levels less than 8.7 nmol/h/mg protein. In our experience some carriers will also have less than 8.7 nmol/h/mg protein activity.

Clinical Reference

1. Martins AM, Valadares ER, Porta G, et al: Recommendations on diagnosis, treatment, and monitoring for Gaucher disease. J Pediatr 2009 Oct;155(4 Suppl):S10-S18

2. Grabowski GA, Petsko GA, Kolodny EH: Chapter 146: Gaucher Disease. In Scriver's The Online Metabolic and Molecular Basis of Inherited Disease. Edited by D Valle, AL Beaudet, B Vogelstein, et al. New York, McGraw-Hill Medical Division. Accessed 3/17/2015. Available at www.ommbid.com

3. Pastores GM, Hughes DA: Gaucher disease. In GeneReviews. Edited by RA Pagon, MP Adam, HH Ardinger, et al. University of Washington. Accessed 3/17/2015. Available at www.ncbi.nlm.nih.gov/books/NBK1269/

4. Weinreb NJ, Andersson HC, Banikazemi M, et al: Prevalence of type 1 Gaucher disease in the United States. Arch Intern Med 2008;168:326-328

Analytic Time

8 days

Method Name

Fluorometric

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