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Test Code LGB3S Globotriaosylsphingosine, Serum


Advisory Information


This test is not useful for determining carrier status. Order FABRZ / Fabry Disease, Full Gene Analysis for carrier testing.



Necessary Information


1. Patient’s age is required.

2. Reason for referral is required.



Specimen Required


Patient Preparation: Fasting 12 hours

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL


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.

Secondary ID

65532

Useful For

Diagnosis and monitoring of Fabry disease

Testing Algorithm

The following algorithms are available in Special Instructions:

-Fabry Disease: Newborn Screen-Positive Follow-up

-Fabry Disease Testing Algorithm

Method Name

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

Reporting Name

Lyso-GB3, S

Specimen Type

Serum

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 90 days
  Refrigerated  24 hours

Reject Due To

Hemolysis

Mild OK; Gross OK

Lipemia

Mild OK; Gross reject

Icterus

Mild OK, Gross OK

Other

NA

Clinical Information

Fabry disease is an X-linked recessive lysosomal storage disorder caused by a deficiency of the enzyme alpha-galactosidase A (alpha-Gal A). Reduced enzyme activity results in accumulation of glycosphingolipids in the lysosomes throughout the body, in particular, the kidney, heart, and brain. Severity and onset of symptoms are dependent on the residual enzyme activity. Symptoms may include acroparesthesias (pain crises), multiple angiokeratomas, reduced or absent sweating, corneal opacity, renal insufficiency leading to end-stage renal disease, and cardiac and cerebrovascular disease. There are renal and cardiac variant forms of Fabry disease that may be underdiagnosed. Heterozygous females of Fabry disease can have clinical presentations ranging from asymptomatic to severely affected, and they may have alpha-Gal A activity in the normal range. The estimated incidence varies from 1 in 3,000 infants detected via newborn screening to 1 in 10,000 males diagnosed after onset of symptoms.

 

Unless irreversible damage has already occurred, treatment with enzyme replacement therapy (ERT) has led to significant clinical improvement in affected individuals. For this reason, early diagnosis and treatment are desirable, and in a few US states early detection of Fabry disease through newborn screening has been implemented.

 

Absent or reduced alpha-Gal A in blood spots, leukocytes (AGA / Alpha-Galactosidase, Leukocytes), or serum (AGAS / Alpha-Galactosidase, Serum) can indicate a diagnosis of classic or variant Fabry disease. Molecular sequence analysis of the GLA gene (FABRZ / Fabry Disease, Full Gene Analysis) allows for detection of the disease-causing mutation in males and females. Molecular genetic testing is the recommended diagnostic test for females as alpha-galactosidase activity may be in the normal range in an affected female patient. 

 

The glycosphingolipid, globotriaosylsphingosine (LGb3), may be elevated in symptomatic patients and supports a diagnosis of Fabry disease. It may also be helpful as a tool for monitoring disease progression as well as determining treatment response in known patients. In addition, measurement or globotriaosylsphingosine (LGb3), may provide additional diagnostic information in the evaluation of uncertain cases, such as in asymptomatic heterozygous females, individuals with novel GLA variants of unclear clinical significance, as well as asymptomatic patients identified by family screening.

Reference Values

≤1.0 ng/mL

Interpretation

Elevation of globotriaosylsphingosine (Lyso-GB3)is diagnostic for Fabry disease.

Clinical Reference

1. Aerts JM, Groener JE, Kuiper S, et al:  Elevated globotriaosylsphingosine is a hallmark of Fabry disease.  Proc Natl Acad Sci USA 2008;105(8)2812-2817

2. Mehta A, Hughes DA: Fabry Disease. In GeneReviews. 2002 Aug 5, Updated 2013 Oct 17. Edited by RA Pagon, MP Adam, HH Ardinger, et al: Seattle, WA. University of Washington, Seattle; 1993-2015. Accessed 6/21/17. Available at www.ncbi.nlm.nih.gov/books/NBK1292/

3. Laney DA, Bennett RL, Clarke V, et al: Fabry disease practice guidelines: recommendations of the National Society of Genetic Counselors. J Genet Couns 2013;22:555-564

4. Laney DA, Peck DS, Atherton AM, et al: Fabry disease in infancy and early childhood: a systematic literature review. Genet Med 17(5) 323-330. Accessed 6/21/17. Available at www.nature.com/gim/journal/vaop/ncurrent/pdf/gim2014120a.pdf

Day(s) and Time(s) Performed

Varies

Analytic Time

8 days

Performing Laboratory

Mayo Medical Laboratories in Rochester

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
LGB3S Lyso-GB3, S In Process

 

Result ID Test Result Name Result LOINC Value
BG708 Reason for Referral 42349-1
65532 Lyso-GB3, S In Process
113176 Interpretation (LGB3S) 59462-2
113177 Reviewed By 18771-6