FUCW - Clinical: Alpha-Fucosidase, Leukocytes

Test Catalog

Test Name

Test ID: FUCW    
Alpha-Fucosidase, Leukocytes

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

Detection of fucosidosis

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

Not available for carrier detection.

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

Fucosidosis is an autosomal recessive lysosomal storage disorder caused by reduced or absent alpha-L-fucosidase enzyme activity. This enzyme is involved in degrading asparagine-linked, fucose-containing complex molecules (oligosaccharides, glycoasparagines) present in cells. Reduced or absent activity of this enzyme results in the abnormal accumulation of these molecules in the tissues and body fluids.


Severe and mild subgroups of fucosidosis, designated types I and II, have been described, although recent data suggests individual patients may represent a continuum within a wide spectrum of severity. The more severe type is characterized by infantile onset, rapid psychomotor regression, and severe neurologic deterioration. Additionally, dysostosis multiplex and elevated sweat sodium chloride are frequent findings. Death typically occurs within the first decade of life. Those with the milder phenotype express comparatively mild psychomotor and neurologic regression, radiologic signs of dysostosis multiplex and skin lesions (angiokeratoma corporis diffusum). Normal sweat salinity, the presence of the skin lesions, and survival into adulthood most readily distinguish milder from more severe phenotypes. Although the disorder is panethnic, the majority of reported patients with fucosidosis have been from Italy and southwestern United States. To date, about 100 cases have been reported worldwide.


An initial diagnostic workup includes a multianalyte or multienzyme screening assay for several oligosaccharidoses, including fucosidosis, in urine, leukocytes, or fibroblasts (OLIGU / Oligosaccharide Screen, Urine; OLIWB / Oligosaccharidoses Screen, Leukocytes or OLITC / Oligosaccharidoses Screen, Fibroblasts). If the screening assay is suggestive of fucosidosis, enzyme analysis of alpha-L-fucosidase can confirm the diagnosis.

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 =0.32 nmol/min/mg protein

Interpretation Provides information to assist in interpretation of the test results

Values below 0.32 nmol/min/mg protein are consistent with a diagnosis of fucosidosis.

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

This test cannot be used to establish carrier status for fucosidosis.

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

1. Cowan TM, Yu C: Laboratory investigations of inborn errors of metabolism. In Pediatric Endocrinology and Inborn Errors of Metabolism. Edited by K Sarafoglou, GF Hoffmann, KS Roth, New York, McGraw-Hill Medical Division, 2009, pp 867-868

2. Enns GM, Steiner RD, Cowan TM: Lysosomal disorders. In Pediatric Endocrinology and Inborn Errors of Metabolism. Edited by K Sarafoglou, GF Hoffmann, KS Roth, New York, McGraw-Hill Medical Division, 2009, pp 747-748

3. Thomas GH: Chapter 140: Disorders of Glycoprotein Degradation: alpha-mannosidosis, beta-mannosidosis, fucosidosis, and sialidosis. In Scriver's The Online Metabolic and Molecular Basis of Inherited Disease (OMMBID). Edited by D Valle, AL Beaudet, B Vogelstein, et al. McGraw-Hill Medical Division. Accessed 3/19/2015. Available at www.ommbid.com/

Special Instructions and Forms Library of PDFs including pertinent information and consent forms, specimen collection and preparation information, test algorithms, and other information pertinent to test