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Diagnostic Services

Genetics Lab


Metachromatic Leukodystrophy Enzyme Assay

Metachomatic leukodystrophy is a progressive disorder of sulfatide metabolism affecting primarily the nervous system. The age of onset varies from late-infancy to adulthood and all subtypes include progressive neurological deterioration such as hypotonia/muscle weakness, gait problems, and behavioral changes.

Test Name: MLD (Arylsulfatase A)
Test Code:
Test Description:
Quantitative measurement of arylsulfatase A enzyme in white blood cells or cultured skin fibroblasts.
MLD, leukodystrophy
This test is indicated for diagnostic testing of individuals with some or all of the following:
-progressive neurological dysfunction and MRI evidence of white matter disease
-elevated urine sulfatides
-metachromatic lipid storage in nervous system tissue
Related Tests:
Clinical Links: Arylsulfatase A Deficiency GeneReview
Mon - Fri
Turnaround Time:
7-10 days
Colorimetric enzyme assay
Reference Range:
Interpretive report provided
Consent Form:
Sample Requirements: Type
Whole blood: 5-10 ml, ACD (yellow) or Heparin (green) tube. Do NOT use gel separator tubes.
Fibroblasts: 2 T-25 flasks
Skin biopsy: 2-4 mm 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:
Monday – Friday 8 am – 5 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