Galactocerebrosidase, WBC - Clinical Genetic Test - GTR

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Galactocerebrosidase, WBC

Clinical Genetic Test

offered by

Mayo Clinic Laboratories

View lab's test page

GTR Test Accession: GTR000597471.2

INHERITED DISEASEOPHTHALMOLOGYNERVOUS SYSTEM ... View more

Last updated in GTR: 2024-04-25

Last annual review date for the lab: 2023-05-30

At a Glance

Test purpose:

Diagnosis

Conditions (1):

Galactosylceramide beta-galactosidase deficiency

Analytes (1):

galactocerebrosidase (GALC)

Methods (1):

Biochemical Genetics - Enzyme assay: Liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Target population:

Diagnosis of Krabbe disease. Follow-up testing for evaluation of an …

Clinical validity:

Not provided

Clinical utility:

Establish or confirm diagnosis

Ordering Information

Offered by:

Mayo Clinic Laboratories
View lab's website
View lab's test page

Test short name:

GALCW

Specimen Source:

Peripheral (whole) blood
View specimen requirements

Who can order:

Genetic Counselor
Health Care Provider
Licensed Dentist
Licensed Physician
Nurse Practitioner
Physician Assistant
Public Health Mandate
Registered Nurse

Test Order Code:

GALCW
View other test codes

LOINC codes:

**LOINC codes notice

Lab contact:

Gisele (Gessi) Bentz Pino, MS, CGC, Certified Genetic counselor, CGC, Genetic Counselor
biochemicalgenetics@mayo.edu
1-800-533-1710

Contact Policy:

Laboratory can only accept contact from health care providers. Patients/families are encouraged to discuss genetic testing options with their health care provider.

How to Order:

https://www.mayocliniclabs.com/test-catalog/overview/606270#Specimen
Order URL

Test development:

Test developed by laboratory (no manufacturer test name)

Informed consent required:

Based on applicable state law

Pre-test genetic counseling required:

Decline to answer

Post-test genetic counseling required:

Decline to answer

Recommended fields not provided:

Test strategy

Conditions

Total conditions: 1

Condition/Phenotype	Identifier

Test Targets

Analytes

Total analytes: 1

Analyte	Associated Condition

Methodology

Total methods: 1

Method Category

Test method

Instrument *

Enzyme assay

Liquid chromatography-tandem mass spectrometry (LC-MS/MS)

* Instrument: Not provided

Clinical Information

Test purpose:

Diagnosis

Clinical utility:

Establish or confirm diagnosis

View citations (3)

Orsini JJ, Escolar ML, Wasserstein MP, Caggana M. Krabbe Disease. 2000 Jun 19 [updated 2018 Oct 11]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. PMID: 20301416.
Liao HC, Spacil Z, Ghomashchi F, Escolar ML, Kurtzberg J, Orsini JJ, Turecek F, Scott CR, Gelb MH. Lymphocyte Galactocerebrosidase Activity by LC-MS/MS for Post-Newborn Screening Evaluation of Krabbe Disease. Clin Chem. 2017;63(8):1363-1369. doi:10.1373/clinchem.2016.264952. Epub 2017 Jun 07. PMID: 28592445.
https://www.ncbi.nlm.nih.gov/books/NBK1238

Target population:

Diagnosis of Krabbe disease. Follow-up testing for evaluation of an abnormal newborn screening result for Krabbe disease. This test is not intended for carrier detection.

View citations (2)

Orsini JJ, Escolar ML, Wasserstein MP, Caggana M. Krabbe Disease. 2000 Jun 19 [updated 2018 Oct 11]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. PMID: 20301416.
Kwon JM, Matern D, Kurtzberg J, Wrabetz L, Gelb MH, Wenger DA, Ficicioglu C, Waldman AT, Burton BK, Hopkins PV, Orsini JJ. Consensus guidelines for newborn screening, diagnosis and treatment of infantile Krabbe disease. Orphanet J Rare Dis. 2018;13(1):30. doi:10.1186/s13023-018-0766-x. Epub 2018 Feb 01. PMID: 29391017.

Recommended fields not provided:

Clinical validity, What is the protocol for interpreting a variation as a VUS?, Are family members with defined clinical status recruited to assess significance of VUS without charge?, Will the lab re-contact the ordering physician if variant interpretation changes?, Is research allowed on the sample after clinical testing is complete?, Sample negative report, Sample positive report

Technical Information

Test Procedure:

The specimens are incubated with a mix of substrate and internal standard for galactocerebrosidase and alpha galactosidase (GLA). The reaction is then stopped using acetonitrile, centrifuged, and a portion of the supernatant is prepared for analysis by liquid chromatography-tandem mass spectrometry. GLA is included to verify sample integrity.(Unpublished Mayo method)

Availability:

Tests performed
Entire test performed in-house

Analytical Validity:

Accuracy was assessed by analysis of positive and negative specimens; all samples were clinically concordant. Intra assay precision was performed at 3 levels: CV results ranged from 2%-3% (N=20 each). Inter assay precision was performed at 3 levels: CV results ranged from 9%-12% (N=20 each). The analytical measurement range is … View more

Assay limitations:

Pseudodeficiency of galactocerebrosidase causes reduced enzymatic activity but does not cause disease. A Krabbe disease phenotype can also be caused in very rare cases by the absence of a physiologically active sphingolipid activator protein, saposin A. Enzyme levels may be normal in individuals who have undergone hematopoietic stem cell transplant.

Proficiency testing (PT):

Is proficiency testing performed for this test?
Yes

Method used for proficiency testing:
Intra-Laboratory

Description of PT method:
Intra-laboratory alternative assessment of performance through quality control or patient blind testing

Description of internal test validation method: Help
This test was laboratory developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements.

Recommended fields not provided:

Test Confirmation, Citations to support assay limitations, Citations to support internal test validation method, Citations for Analytical validity, PT Provider, Major CAP category, CAP category, CAP test list

Regulatory Approval

FDA Review:

Category: FDA exercises enforcement discretion

Additional Information

Reviews:

Genereviews

PubMed Clinical Queries

Clinical resources:

Molecular resources:

View GALC variations in ClinVar

RefSeqGene

Coriell Institute for Medical Research

Practice guidelines:

Consumer resources:

MedlinePlusGenetics (GHR)

NCATS Office of Rare Diseases Research (GARD)

MedlinePlus

IMPORTANT NOTE: NIH does not independently verify information submitted to GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.