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Diagnostic Services

Genetics Lab


Mannosidosis (Beta) Enzyme Assay

Beta-mannosidosis is a glycoprotein storage disorder caused by a deficiency of the beta-mannosidase enzyme. Individuals with beta-mannosidosis do not usually display the typical characteristics of lysosomal storage diseases such as coarse facial features, corneal changes, skeletal changes or hepatosplenomegaly. The most consistent features of beta mannosidosis are mental retardation, history of recurrent respiratory infections and hearing loss. Some individuals may present with angiokeratomas. Individuals with beta-mannosidosis may have an abnormal pattern of urine oligosaccharide excretion. Confirmation of diagnosis is made by measurement of beta-mannosidase enzyme activity directly.

Test Name: Mannosidosis (beta-mannosidosis)
Test Code:
Test Description:
Quantitative measurement of beta-mannosidosis activity in white blood cells and cultured fibroblasts.
mannosidosis; beta mannosidosis; b-mannosidosis
The test is used to confirm the diagnosis in patients with mental retardation, history of recurrent respiratory infections, hearing loss, angiokeratoma or abnormal urine oligosaccharide pattern suggestive of B-mannosidosis.
Related Tests: Oligosaccharides, Urine  
Screening test for symptomatic patients suspected of having a neurodegenerative storage disorder.

Clinical Links: Beta-Mannosidosis OMIM Entry
Turnaround Time:
7-10 days
Fluorometric enzyme assay
Reference Range:
Interpretive report is provided.
Consent Form:
Sample Requirements: Type
Blood: 6-10ml ACD (yellow) or heparin (green) tube. No gel separator tubes
Fibroblasts: 2 T-25 flasks
Skin Biopsy: 2-4mm skin punch biopsy

Keep at room temperature. Do not spin!

Ship overnight at room temperature. Blood sample must be received within 24 hours of collection. Transport fibroblasts/biopsy in appropriate media.
Samples Received:
Mon - Fri 8:00am - 5:00pm PST
For Thursday shipping please arrange for Friday AM delivery.
Special Considerations:
If fresh skin biopsy is submitted, Fibroblast Culture (CH-SKIN) must be ordered separately. Please call to discuss.
Please e-mail Client Services or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Client Services or call at 206-987-2617 with any billing questions