Metachromatic Leukodystrophy (MLD): Arylsulfatase A Enzyme Analysis

Test Information

This biochemical test is a quantitative measurement of arylsulfatase A enzyme activity can be used as a 1st tier test for patients with a clinical suspicion of Metachromatic Leukodystrophy. Demonstration of deficient arylsulfatase A enzyme activity is considered the gold standard to confirm a diagnosis of Metachromatic Leukodystrophy.

Turnaround Time

2 weeks

CPT Code(s)

82657

Cost

$200


Enzymes

Arylsulfatase A

Clinical Information

Metachromatic leukodystrophy is an autosomal recessive condition caused by a deficiency of arylsulfatase A, an enzyme crucial to the breakdown of sulfatides in the body. The accumulation of sulfatides causes demyelination of nerves. Progressive signs of leukodystrophy include a decline in intellectual abilities and motor skills to the extent that affected individuals lose the ability to walk, speak, see, and hear. This condition can present as late-infantile, juvenile or adult forms, and it is more common in people of Israeli or Navajo descent.

Indications

Patients with a suspected diagnosis of metachromatic leukodystrophy based on clinical symptoms and MRI findings.

Methodology

4-methylumbelliferyl substrate

Specimen Requirements

Enzyme activity can be measured in leukocytes or cultured fibroblasts. For leukocytes, please send 5-7 ml of whole blood in a green top (sodium heparin) tube.

Transport Instructions

Whole blood samples for enzyme testing should be shipped at ambient temperature and must arrive at the laboratory the next day.

Have Questions? Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC

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