Test Catalog

Test Id : BGAW

Beta-Galactosidase, Blood

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosis of GM1 gangliosidosis, Morquio syndrome B, and galactosialidosis in whole blood specimens

 

This test is not useful for carrier detection.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

The beta-galactosidase enzyme is deficient in the following conditions: GM1 gangliosidosis, Morquio syndrome B, and galactosialidosis.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

Fluorometric Enzyme Assay

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Beta-Galactosidase, B

Aliases
Lists additional common names for a test, as an aid in searching

B-Galactosidase

Cathepsin A Deficiency

G[M1] Gangliosidosis

Galactosialidosis

Galactosidase, Beta

Generalized Gangliosidosis, G(M1)

GLB1 Deficiency

GM1 Gangliosidosis

Morquio B

Morquio Disease

Morquio Syndrome

Morquio's B

Morquio's Disease

MPS IV

MPS IVB

Mucopolysaccharidosis IVb

PPCA (Protective Protein/Cathepsin A) Deficiency

Protective Protein Deficiency

Protective Protein/Cathepsin A (PPCA) Deficiency

CTSA Deficiency

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Specimen Type
Describes the specimen type validated for testing

Whole blood

Additional Testing Requirements

Careful review of clinical findings will help distinguish between GM1 gangliosidosis and Morquio syndrome type B. A diagnosis of galactosialidosis must be additionally be ruled out (OLIGU / Oligosaccharide Screen, Random, Urine or LSDGP / Lysosomal Storage Disease Gene Panel, Varies).

Necessary Information

Provide a reason for testing with each specimen.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Container/Tube: 

Preferred: Lavender top (EDTA)

Acceptable: Yellow top (ACD)

Specimen Volume: 2 mL

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Forms

1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) in Special Instructions.

3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 7 days
Refrigerated 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Diagnosis of GM1 gangliosidosis, Morquio syndrome B, and galactosialidosis in whole blood specimens

 

This test is not useful for carrier detection.

Genetics Test Information
Provides information that may help with selection of the correct genetic test or proper submission of the test request

The beta-galactosidase enzyme is deficient in the following conditions: GM1 gangliosidosis, Morquio syndrome B, and galactosialidosis.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Beta-galactosidase is a lysosomal enzyme responsible for catalyzing the breakdown of gangliosides. Isolated deficiency of this enzyme is expressed clinically as 2 different autosomal recessive diseases, GM1 gangliosidosis and Morquio syndrome B (mucopolysaccharidosis IVB [MPS IVB] or Morquio B). Galactosialidosis (GS) is associated with a combined deficiency of beta-galactosidase and neuraminidase secondary to a defect in protective protein cathepsin A (PPCA). Enzymatic testing is not reliable for carrier detection of these conditions.

 

In GM1 gangliosidosis, reduced or absent beta-galactosidase activity leads to the accumulation of GM1 gangliosides, oligosaccharides, and keratan sulfate. The disorder can be classified into 3 subtypes that vary with respect to age of onset and clinical presentation. Type 1, or infantile onset, typically presents between birth and 6 months of age with a very rapid progression of hypotonia, dysostosis multiplex, hepatosplenomegaly, central nervous system degeneration, and death usually by 1 to 2 years old. Type 2 is generally classified as late infantile or juvenile with onset between 7 months and 3 years of age presenting with developmental delays and a slower progression. Type 3 is an adult or chronic variant with onset between 3 and 30 years of age and is typically characterized by slowly progressive dementia with Parkinsonian features and dystonia. The incidence has been estimated to be 1 in 100,000 to 200,000 live births.

 

In Morquio B, reduced or absent beta-galactosidase activity leads to the accumulation of glycosaminoglycans (GAG), particularly keratan sulfate, in lysosomes and interferes with normal functioning of cells, tissues, and organs. Morquio B typically manifests as a systemic skeletal disorder with variable severity ranging from early severe disease to a later onset attenuated form. Virtually all patients have dysostosis multiplex and short stature along with other symptoms that may include coarse facies, hepatosplenomegaly, hoarse voice, stiff joints, cardiac disease, but no neurological involvement.

 

Galactosialidosis is an autosomal recessive lysosomal storage disease caused by variants in the cathepsin A gene (CTSA) resulting in a combined deficiency of the enzymes beta-galactosidase and neuraminidase. The disorder can be classified into 3 subtypes that vary with respect to age of onset and clinical presentation. Typical clinical presentation includes coarse facial features, cherry-red spots, and skeletal dysplasia. The early infantile form is associated with fetal hydrops, visceromegaly, skeletal dysplasia, and early death, while the late infantile form is characterized by short stature, dysostosis multiplex, coarse facial features, corneal clouding, hepatosplenomegaly, and/or heart valve problems. Individuals of Japanese ancestry make up the majority of patients with the juvenile/adult form of GS and typically develop symptoms after 4 years of age. These include neurologic degeneration, ataxia, and angiokeratomas.

 

A diagnostic workup in an individual with GM1 gangliosidosis, Morquio B, or GS typically demonstrates decreased beta-galactosidase enzyme activity in leukocytes or fibroblasts; however, additional testing and consideration of the patient's clinical findings are necessary to differentiate between these conditions. Follow-up testing may include LSDS / Lysosomal Storage Disorders Screen, Random, Urine, which analyzes urine mucopolysaccharides, oligosaccharides, ceramide trihexosides, and sulfatides. The LSDS test can help differentiate between the 3 conditions to guide physicians in choosing the best confirmatory molecular testing option. See Lysosomal Storage Disorders Diagnostic Algorithm, Part 1 in Special Instructions.

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 =5.0 nmol/hour/mL

An interpretive report will be provided.

Interpretation
Provides information to assist in interpretation of the test results

Results below 5.0 nmol/hour/mL in properly submitted specimens are consistent with beta-galactosidase deficiency (GM1 gangliosidosis, Morquio syndrome B, or galactosialidosis). Further differentiation between GM1, Morquio syndrome B, and galactosialidosis is dependent on the patient's clinical findings and results of additional biochemical testing.

 

Normal results (> or =5.0 nmol/h/mL) are not consistent with beta-galactosidase deficiency.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test cannot reliably determine carrier status.

 

This test does not differentiate between GM1 gangliosiosis, MPS IVB, and galactosialidosis.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Suzuki Y, Nanba E, Matsuda J, et al: Beta-galactosidase deficiency (beta-galactosidosis): GM1 gangliosidosis and Morquio B disease. In: Valle D, Antonarakis S, Ballabio A, Beaudet A, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed February 04, 2021. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225547263

2. Regier DS, Tifft CJ: GLB1-related disorders. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2013. Updated August 29, 2019. Accessed February 04, 2021. Available at www.ncbi.nlm.nih.gov/books/NBK164500

3. d'Azzo A, Andria G, Bonten E, Annunziata I: Galactosialidosis. In: Valle D, Antonarakis S, Ballabio A, Beaudet A, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed February 04, 2021. Available at https://ommbid.mhmedical.com/content.aspx?sectionid=225547663

4. Arash-Kaps L, Komlosi K, Seegraber M, et.at: The clinical and molecular spectrum of GM1 gangliosidosis. Pediatr. 2019 Dec;215:152-157.e3. doi: 10.1016/j.jpeds.2019.08.016

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

Whole blood collected in ACD or EDTA anticoagulant tubes is spotted onto filter paper and dried overnight. A one-eighth inch (3-mm) disk is punched out of the dried blood spot (DBS) into a 96-well, round-bottom plate with citrate-phosphate buffer as elution liquid and 4-methylumbelliferyl-beta-D-galactopyranoside in water as the substrate. A blank is prepared using only elution liquid, substrate, and filter paper punches containing no blood. All patients, controls, and blank are set up in duplicate. After the incubation period, the liquid from the plate is transferred to a 96-well, flat-bottom black plate. A calibration curve is prepared and analyzed on every plate to calculate enzyme activity results, based on fluorescence units in patient wells vs calibrators. The calibration is derived from 4-methylumbelliferone (4-MU) that is serially diluted manually in the plate with the highest calibrator being equivalent to an enzyme activity of 10.4 nmol/hour/mL. Stop buffer is added to all wells (patients, quality controls, blanks, calibrators). The plate is then read on the spectrofluorometer. Fluorescence readings for duplicate wells are averaged, and the average fluorescence is used to calculate the enzyme activity result.(Civallero G, Michelin K, de Mari J, et al: Twelve different enzyme assays on dried-blood filter paper samples for detection of patients with selected inherited lysosomal storage diseases. Clin Chim Acta. 2006 Oct;372(1-2):98-102; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KD, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Preanalytical processing: Monday through Saturday

Assay performed: Tuesday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

8 to 15 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

1 year

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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 US Food and Drug Administration.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

82657

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports