Fabry Disease: Alpha-galactosidase Enzyme Analysis

Test Information

This biochemical test is a quantitative measurement of alpha-galactosidase enzyme activity and can be used as a 1st tier test for patients with a clinical suspicion of Fabry disease. Demonstration of deficient alpha-galactosidase enzyme activity is considered the gold standard to confirm a diagnosis of Fabry disease.

 

In addition, this assay can be used to clarify molecular findings in the GLA gene, to follow up abnormal newborn screening results, and to monitor patients undergoing treatment.

Turnaround Time

2 weeks

CPT Code(s)

82657

Cost

$200


Enzymes

Alpha-galactosidase

Disorders

Clinical Information

Fabry disease is a lysosomal storage disorder in which absent or reduced production of alpha-galactosidase A leads to the systemic accumulation of globotriaoslyceramide. Total absence of enzyme production results in the more severe, classic form of Fabry disease, while reduced production of alpha-galactosidase A typically often involves milder symptoms that appear later in life. Episodic pain, angiokeratosis, and hypohydrosis are frequently seen in patients with Fabry disease as well as corneal clouding and hearing loss. Gastrointestinal issues and breathing problems are common, and complications including cardiac abnormalities, kidney disease, and strokes can be life-threatening. Although Fabry disease is an X-linked disorder that primarily affects males, carrier females may become symptomatic. This condition occurs in approximately 1 in 55,000 males, and the development of enzyme replacement therapy has greatly improved the prognosis for many patients.

Indications

This test can be used to confirm a suspected Fabry disease diagnosis.

Methodology

4-methylumbelliferyl substrate.

Specimen Requirements

Enzyme activity can be measured in plasma, leukocytes, cultured fibroblasts, or dried blood spots. For plasma or leukocytes, please send 5-10 ml of whole blood in a green top (sodium heparin) tube, or spin down a whole blood sample, pull off the plasma, and freeze. For dried blood spot collection, a minimum of three circles need to be filled in. Each circle should contain one drop of blood (about 100 microliters). See the link below for additional sample collection and handling instructions.

Transport Instructions

Whole blood samples (for leukocyte analysis) should be shipped at ambient temperature and must arrive at the laboratory the next day. If plasma has been separated and frozen, send frozen via overnight shipping, preferably on dry ice. Cultured fibroblasts should be sent overnight at room temperature. For a dried blood spot: When the sample has dried 3-4 hours, fold cover at score line, over sample, and tuck into flap. Samples can be mailed at ambient temperature.

Have Questions? Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC

Lucy's Story

When our daughter Lucy had a metabolic crisis at 7 days old, we were shocked and devastated to find out that she was born with a rare genetic disorder (MSUD). Her newborn screening results did not make it back in time to prevent the crisis, and no one at our local hospital was familiar with the disease. They did not know how to treat her. Calls were made to Greenwood Genetic Center to confirm her diagnosis and guide her care. Dr. Champaigne and Ami...

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