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.

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