α-Galactosidase A
Related Gene(s): GLA
Fabry disease is an X-linked lysosomal storage disorder caused by a marked deficiency of α-galactosidase A enzyme activity. Affected individuals are unable to degrade globotriaosylceramide (GL-3, also called Gb3) and related glycolipids in their lysosomes. The progressive accumulation of GL-3 and its derivative, lyso-GL-3, results in symptoms that include characteristic skin lesions (angiokeratomas), decreased sweating (hypohidrosis), chronic fatigue, depression, neuropathic pain in the hands and feet (acroparesthesia), gastrointestinal issues, strokes, cardiac disease (including left ventricular hypertrophy, leading to hypertrophic cardiomyopathy), and renal disease (proteinuria to end stage renal disease).
Fabry disease affects both men and women (heterozygotes), but the testing strategy varies based on sex. α-galactosidase A enzyme analysis alone detects all affected males, but is not reliable for the detection of Fabry disease in heterozygotes. Sequencing of the α-galactosidase A gene is recommended for the diagnosis of females with Fabry disease. Flurometric enzyme analysis using artificial substrate 4-methylumbelliferyl-galactopyranoside is used to measure glucosidase activity. Both plasma and leukocyte enzyme activity are measured in this assay.
Specimen Requirements
Postnatal
- Whole blood: Two 5-10 mL tubes with sodium heparin (green top)
Ordering Information
Shipping
- Ship whole blood at room temperature. Blood samples must be received within 48 hours of collection
- If the sample cannot be sent immediately, prepare and freeze plasma and leukocyte pellets until shipment. Then, ship frozen on dry ice
Turnaround Time
- 7-10 days
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