Detection of fucosidosis
This test is not useful for establishing carrier status for fucosidosis.
Fucosidosis is an autosomal recessive lysosomal storage disorder caused by reduced or absent alpha-L-fucosidase enzyme activity.
Determining enzymatic activity is the next step of the diagnostic workup for an individual clinically suspicious for an oligosaccharidosis and with a positive screening result suggestive of fucosidosis.
Fluorometric
Alpha-L-Fucosidase
Fucosidase
Fucosidase, Alpha
Fucosidosis
Whole Blood ACD
If clinically suspicious of an oligosaccharidosis, a screening test is available. Order OLIGU / Oligosaccharide Screen, Random, Urine.
For optimal isolation of leukocytes, it is recommended the specimen arrive refrigerate within 6 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.
Container/Tube:
Preferred: Yellow top (ACD solution B)
Acceptable: Yellow top (ACD solution A)
Specimen Volume: 6 mL
Collection Instructions: Send specimen in original tube. Do not aliquot.
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
5 mL
Gross hemolysis | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood ACD | Refrigerated (preferred) | 6 days | YELLOW TOP/ACD |
Ambient | 6 days | YELLOW TOP/ACD |
Detection of fucosidosis
This test is not useful for establishing carrier status for fucosidosis.
Fucosidosis is an autosomal recessive lysosomal storage disorder caused by reduced or absent alpha-L-fucosidase enzyme activity.
Determining enzymatic activity is the next step of the diagnostic workup for an individual clinically suspicious for an oligosaccharidosis and with a positive screening result suggestive of fucosidosis.
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 and 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. Fucosidosis is an autosomal recessive condition resulting from two biallelic pathogenic variants in the FUCA1 gene. 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 urine screening assay for several oligosaccharidosis (OLIGU / Oligosaccharide Screen, Random, Urine). If the screening assay is suggestive of fucosidosis, enzyme analysis of alpha-L-fucosidase can confirm the diagnosis.
> or =0.32 nmol/min/mg protein
Values below 0.32 nmol/min/mg protein are consistent with a diagnosis of fucosidosis.
No significant cautionary statements
1. Enns GM, Steiner RD, Cowan TM: Lysosomal disorders. In: Sarafoglou K, Hoffmann GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. McGraw-Hill Medical Division; 2009:747-748
2. Thomas GH: Disorders of glycoprotein degradation: Alpha-mannosidosis, beta-mannosidosis, fucosidosis, and sialidosis. In: Valle DL, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed February 17, 2022. Available at: https://ommbid.mhmedical.com/content.aspx?sectionid=225545029
3. Stepien KM, Ciara E, Jezela-Stanek A. Fucosidosis-clinical manifestation, long-term outcomes, and genetic profile-review and case series. Genes (Basel). 2020 Nov 22;11(11):1383. doi: 10.3390/genes11111383
Incubation of 4-methylumbelliferyl-alpha-L-fucopyranoside with cell homogenates results in cleavage of the substrate by alpha-L-fucosidase yielding 4-methylumbelliferone (4-MU) and fucose. Free 4-MU can be quantitated by measurement of the fluorescence.(Beratis NG, Turner BM, Labadie G, Hirschhorn K: a-L-fucosidase in cultured skin fibroblasts from normal subjects and fucosidosis patients. Pediatr Res. 1977 Jul;11[7]:862-866; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS. Eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)
Preanalytical processing: Monday through Saturday
Assay performed: Once per month
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
82657
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
FUCW | Alpha-Fucosidase, Leukocytes | 24047-3 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
8814 | Alpha-Fucosidase, Leukocytes | 24047-3 |
35635 | Interpretation (FUCW) | 59462-2 |
35634 | Reviewed By | 18771-6 |