Diagnosis of Gaucher disease
Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request
Not recommended for carrier detection; instead order GAUP / Gaucher Disease, Mutation Analysis, GBA.
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
When this test is ordered, a fibroblast culture and cryopreservation for biochemical studies will always be performed at an additional charge. However, for multiple lysosomal enzyme assays on a patient utilizing fibroblast culture, only 1 culture is required regardless of the number of enzyme assays ordered. If viable cells are not obtained within 10 days, client will be notified.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 the accumulation of undigested materials (primarily 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 bone disease, hepatosplenomegaly, and 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 prior to 2 years, with 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. In addition, 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 and/or substrate reduction 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 1 in 200,000 in the general population, but is much more frequent among Ashkenazi Jews with an incidence ranging from 1 in 400 to 1 in 900. Types 2 and 3 both have an incidence of approximately 1 in 100,000 in the general population.
A diagnostic work up for Gaucher disease may demonstrate the characteristic finding of "Gaucher cells" on bone marrow examination. Reduced or absent enzyme activity of acid beta-glucosidase is diagnostic. 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 GBA (GBAZ / Gaucher Disease, Full Gene Analysis) allows for detection of disease-causing mutations in affected patients for whom a targeted mutation panel identifies a single or no mutation.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
> or =4.85 nmol/min/mg protein
Marked deficiency of acid beta-glucosidase is consistent with a diagnosis of Gaucher disease.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Leukocytes are the preferred specimen for the diagnosis of Gaucher disease.
Carrier testing using this assay is not reliable. To determine carrier status, order GAUP / Gaucher Disease, Mutation Analysis, GBA.
Interfering factors include lack of viable cells, bacterial contamination, failure to transport tissue in an appropriate media, excessive transport time, and exposure of the specimen to temperature extremes (freezing or >30 degrees C).
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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: Gaucher Disease. Edited by D Valle, AL Beaudet, B Vogelstein, et al. New York, NY: McGraw-Hill; 2014. Available from http://ommbid.mhmedical.com/content.aspx?bookid=971&Sectionid=62643884. Accessed March 17, 2015
3. Pastores GM, Hughes DA. Gaucher Disease. 2007 In: GeneReviews. Edited by RA Pagon, MP Adam, HH Ardinger, et al. Seattle WA: University of Washington, Seattle;1993-2015. Available from: http://www.ncbi.nlm.nih.gov/books/NBK1269/ Accessed 3/17/2015
4. Weinreb NJ, Andersson HC, Banikazemi M, et al: Prevalence of type 1 Gaucher disease in the United States. Arch Intern Med 2008 Feb 11;168(3):326-327