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Diagnostic Services

Genetics Lab


Mannosidosis (Alpha) Enzyme Assay

Alpha mannosidosis is an autosomal recessive disorder presenting with three clinical subtypes; mild, moderate and severe form. Patients with a milder phenotype have mild-to-moderate mental retardation, characteristic coarse features, skeletal abnormalities, reduced hearing, immunodeficiency, and primary central nervous system disease, mainly cerebellar involvement causing ataxia. Other medical problems include corneal opacities, hepatosplenomegaly, aseptic destructive arthritis, and metabolic myopathy. Alpha-mannosidosis is insidiously progressive; individuals may live into the sixth decade.

Affected individuals may have an abnormal urine oligosaccharide pattern. Confirmation is made by measurement of alpha-mannosidosis directly.

Test Name: Mannosidosis (alpha-mannosidase)
Test Code:
Test Description:
Quantitative measurement of alpha-mannosidosis enzyme activity in white blood cells or cultured fibroblasts.
The test is indicated for individuals with some or all of the following:
-mental retardation
-skeletal abnormalities
-hearing loss
-cerebellar ataxia
-abnormal urine oligosaccharide pattern.
This test is not appropriate for determining carrier status or for prenatal diagnosis.
Related Tests: Oligosaccharides, Urine  
This screening test is used for symptomatic patients suspected of having a neurodegenerative storage disorder.

Clinical Links: Alpha-Mannosidosis GeneReview
Turnaround Time:
7-10 days
Fluorometric enzyme assay
Reference Range:
Interpretative report is provided.
Consent Form:
Sample Requirements: Type
Whole blood: 10 mL ACD (yellow) or heparin (green) tube. Do not use gel separator tubes.
Fibroblasts: 2 T-25 flasks.
Skin biopsy: 2-4mm skin punch biopsy

Do not spin! Keep at room temperature.

Ship overnight at room temperature. Blood sample MUST be received within 24 hours of collection.
Ship fibroblasts/biopsy in appropriate cell culture/transport media
Samples Received:
Mon – Fri 8:00 am – 5:00 pm PST
Special Considerations:
For Thursday shipping please arrange for AM courier delivery.
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