Gaucher Disease : Beta-glucosidase Enzyme Analysis

Test Information

This biochemical test is a quantitative measurement of beta-glucosidase enzyme activity can be used as a 1st tier test for patients with a clinical suspicion of Gaucher disease. Demonstration of deficient beta-glucosidase enzyme activity is considered the gold standard to confirm a diagnosis of Gaucher disease.

In addition, this assay can be used to clarify molecular findings in the GBA gene, to follow up abnormal newborn screening results, and to monitor patients undergoing treatment.

Turnaround Time

2 weeks

CPT Code(s)

82963

Cost

$200


Enzymes

Beta-glucosidase

Clinical Information

Gaucher disease, a lysosomal storage disorder, can present with a wide spectrum of severity ranging from a perinatal lethal phenotype to asymptomatic. There are three primary types with two additional subtypes, all categorized by differences in the clinical presentation of the patient. Hepatosplenomegaly, pulmonary disease, and cytopenia are also common for most types of Gaucher disease.

Patients with Gaucher disease type 1 have varying degrees and types of bone disease as the primary feature, but do not have any central nervous system involvement. Gaucher disease types 2 and 3 present with primary neurologic disease. Type 2 and 3 are distinguished based on age of onset and disease progression. Patients with type 2 typically have an earlier onset before age 2, rapid disease progression, and early death. Type 3 is characterized by a slower disease course with patients living into adulthood. Neurologic findings for types 2 & 3 include bulbar signs, pyramidal signs, oculomotor apraxia, seizures, as well as dementia and ataxia in later disease stages. The perinatal lethal form may present as nonimmune hydrops fetalis or with pyramidal neurologic signs and ichthyosiform skin changes. The cardiovascular form is characterized by primarily by calcification of mitral and aortic values with other minor findings.

Indications

Biomarker analysis of chitotriosidase can be used to monitor disease progression for affected individuals including those receiving enzyme replacement therapy.

Methodology

4-methylumbelliferyl substrate

Specimen Requirements

Enzyme activity can be measured in leukocytes, cultured fibroblasts, or dried blood spots. For leukocytes, please send 5-10 ml of whole blood in a green top (sodium heparin) tube. For dried blood spot collection, a minimum of three circles need to be filled in. Each circle should contain one drop of blood (about 100 microliters). See the link below for additional sample collection and handling instructions.

Transport Instructions

Whole blood samples (for leukocyte analysis) should be shipped at ambient temperature and must arrive at the laboratory within 24 hours of specimen collection.

Cultured fibroblasts should be sent overnight at room temperature.

For a dried blood spot: When the sample has dried 3-4 hours, fold cover at score line, over sample, and tuck into flap. Samples can be mailed at ambient temperature.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Biochemical Testing, Enzyme Analysis, Individual Enzyme Assays
One Mother's Story

One Mother's Story

After a long three-year struggle trying to have children, our son, Charlie, was born on April 18, 2009. He was our miracle...perfect in every way! When Charlie was five days old, our pediatrician called to notify us that one of the numbers from the heel prick test was a bit high. We headed to the hospital that afternoon for more tests. I will never forget the following day. It was cool and crisp - not a cloud in the sky....

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