Beta-Galactosidase, Leukocytes

Casandra

Casandra Test Code MC20157Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID BGACPT Code 82657

Beta-Galactosidase, Leukocytes

Clinical Use

Use

This test aids in the diagnosis of GM1 gangliosidosis, Morquio B disease, and galactosialidosis. Beta-galactosidase is a lysosomal enzyme responsible for catalyzing the hydrolysis of gangliosides. Deficiency of this enzyme leads to significant clinical disorders including GM1 gangliosidosis, which can present as infantile, juvenile, or adult onset with varying symptoms, and Morquio syndrome B, which primarily involves skeletal dysplasia. Galactosialidosis also involves deficiency in this enzyme coupled with neuraminidase deficiency, resulting in neurological and skeletal anomalies.

Special Instructions

The test is available for New York state clients and requires informed consent for genetic testing. Specimens should be collected and shipped with optimal timing to maintain integrity, preferably from Monday through Thursday. A completed Biochemical Genetics Test Request form must accompany the specimen if not ordered electronically.

Limitations

This test is not suitable for carrier detection. It does not differentiate between GM1 gangliosidosis, Morquio B, and galactosialidosis on its own. Additional enzymatic or genetic testing may be required to fully interpret low beta-galactosidase activity levels and confirm a diagnosis. Measurement of beta-galactosidase enzyme activity is not the preferred diagnostic test for I-cell disease but can be a part of the testing strategy.

Test Details

New York Approved

Methodology

Automated Analyzer (Fluorometric)

Biomarkers

The deficiency of beta-galactosidase is measurable using 4-methylumbelliferyl-beta-D-galactopyranoside as a substrate, quantifying the released 4-methylumbelliferone.

Beta-Galactosidase

Analyte

Enzyme Activity • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)