Skip Navigation
Genetics Home Reference: your guide to understanding genetic conditions About   Site Map   Contact Us
Home A service of the U.S. National Library of Medicine®
Printer-friendly version


Reviewed February 2013

What is the official name of the ARSA gene?

The official name of this gene is “arylsulfatase A.”

ARSA is the gene's official symbol. The ARSA gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the ARSA gene?

The ARSA gene provides instructions for making the enzyme arylsulfatase A. This enzyme is located in cellular structures called lysosomes, which are the cell's recycling centers. Within lysosomes, arylsulfatase A helps process substances known as sulfatides. Sulfatides are a subgroup of sphingolipids, a category of fats that are important components of cell membranes. Sulfatides are abundant in the nervous system's white matter, consisting of nerve fibers covered by myelin. Myelin, made up of multiple layers of membranes, insulates and protects nerves.

How are changes in the ARSA gene related to health conditions?

metachromatic leukodystrophy - caused by mutations in the ARSA gene

More than 110 mutations that cause metachromatic leukodystrophy, a disorder that causes deterioration of nervous system functions, have been identified in the ARSA gene. These mutations greatly reduce the activity of arylsulfatase A. Severe disruption in arylsulfatase A activity interferes with the breakdown of sulfatides. As a result, these substances can accumulate to toxic levels in the nervous system. The buildup of sulfatides gradually destroys the cells that produce myelin, the covering that protects nerves and promotes the efficient transmission of nerve impulses. Destruction of myelin leads to the loss of white matter (leukodystrophy) and impairment of nervous system function, resulting in the signs and symptoms of metachromatic leukodystrophy.

In some cases, individuals with very low arylsulfatase A activity show no signs or symptoms of metachromatic leukodystrophy. This condition, called pseudoarylsulfatase deficiency, seems to be caused by specific variations of the ARSA gene. These variations are present in as many as 5 to 10 percent of Europeans and North Americans.

Where is the ARSA gene located?

Cytogenetic Location: 22q13.33

Molecular Location on chromosome 22: base pairs 50,622,754 to 50,628,173

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The ARSA gene is located on the long (q) arm of chromosome 22 at position 13.33.

The ARSA gene is located on the long (q) arm of chromosome 22 at position 13.33.

More precisely, the ARSA gene is located from base pair 50,622,754 to base pair 50,628,173 on chromosome 22.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about ARSA?

You and your healthcare professional may find the following resources about ARSA helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the ARSA gene or gene products?

  • cerebroside 3-sulfatase
  • Cerebroside-3-sulfate 3-sulfohydrolase
  • Cerebroside-Sulfatase
  • MLD
  • sulfatidase

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding ARSA?

breakdown ; cell ; deficiency ; enzyme ; gene ; leukodystrophy ; nervous system ; sulfate ; toxic ; white matter

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (11 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: February 2013
Published: February 8, 2016