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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2008

What is the official name of the ASPA gene?

The official name of this gene is “aspartoacylase.”

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

What is the normal function of the ASPA gene?

The ASPA gene provides instructions for making an enzyme called aspartoacylase. In the brain, this enzyme breaks down a compound called N-acetyl-L-aspartic acid (NAA) into aspartic acid (an amino acid that is a building block of many proteins) and another molecule called acetic acid.

The cycle of production and breakdown of NAA appears to be critical for maintaining the brain's white matter, which consists of nerve fibers covered by myelin. Myelin is the fatty substance that insulates and protects nerves. Although the precise function of NAA is unknown, it is probably essential for making certain fats (lipids) that are used to produce myelin. Researchers believe that NAA may also play a role in transporting molecules of water out of nerve cells.

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

Canavan disease - caused by mutations in the ASPA gene

More than 55 mutations in the ASPA gene are known to cause Canavan disease. Two specific mutations cause most cases of the disease in people of Ashkenazi (eastern and central European) Jewish descent. One of these mutations changes a single protein building block (amino acid) in aspartoacylase. Specifically, this mutation replaces the amino acid glutamic acid with the amino acid alanine at position 285 of the enzyme (written as Glu285Ala or E285A). The other common mutation, which is written as Tyr231Ter or Y231X, prematurely stops protein production and leads to an abnormally small, nonfunctional version of the enzyme.

A different mutation is most common in people who are not of Ashkenazi Jewish descent. This mutation substitutes the amino acid glutamic acid for the amino acid alanine at position 305 of aspartoacylase (written as Ala305Glu or A305E).

Mutations in the ASPA gene reduce or eliminate the activity of aspartoacylase, which prevents the normal breakdown of NAA in the brain. Recent studies suggest that if NAA is not broken down properly, the resulting chemical imbalance may interfere with the formation of myelin as the nervous system develops. A buildup of NAA also leads to the progressive destruction of existing myelin around nerve cells. Nerve fibers without this protective covering malfunction and die, damaging the brain and causing the serious signs and symptoms of Canavan disease.

Where is the ASPA gene located?

Cytogenetic Location: 17p13.3

Molecular Location on chromosome 17: base pairs 3,474,109 to 3,499,405

The ASPA gene is located on the short (p) arm of chromosome 17 at position 13.3.

The ASPA gene is located on the short (p) arm of chromosome 17 at position 13.3.

More precisely, the ASPA gene is located from base pair 3,474,109 to base pair 3,499,405 on chromosome 17.

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

Where can I find additional information about ASPA?

You and your healthcare professional may find the following resources about ASPA 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 ASPA gene or gene products?

  • ACY2
  • aminoacylase 2
  • aminoacylase II
  • ASP
  • aspartoacylase (aminoacylase 2, Canavan disease)
  • aspartoacylase (Canavan disease)
  • N-acyl-L-aspartate amidohydrolase

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding ASPA?

alanine ; amino acid ; Ashkenazi Jewish ; Asp ; aspartic acid ; breakdown ; compound ; enzyme ; gene ; glutamic acid ; L-aspartic acid ; molecule ; mutation ; nervous system ; protein ; white matter

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


  • Baslow MH. Brain N-acetylaspartate as a molecular water pump and its role in the etiology of Canavan disease: a mechanistic explanation. J Mol Neurosci. 2003;21(3):185-90. Review. (
  • Bitto E, Bingman CA, Wesenberg GE, McCoy JG, Phillips GN Jr. Structure of aspartoacylase, the brain enzyme impaired in Canavan disease. Proc Natl Acad Sci U S A. 2007 Jan 9;104(2):456-61. Epub 2006 Dec 28. (
  • Hershfield JR, Pattabiraman N, Madhavarao CN, Namboodiri MA. Mutational analysis of aspartoacylase: implications for Canavan disease. Brain Res. 2007 May 7;1148:1-14. Epub 2007 Mar 3. (
  • Madhavarao CN, Arun P, Moffett JR, Szucs S, Surendran S, Matalon R, Garbern J, Hristova D, Johnson A, Jiang W, Namboodiri MA. Defective N-acetylaspartate catabolism reduces brain acetate levels and myelin lipid synthesis in Canavan's disease. Proc Natl Acad Sci U S A. 2005 Apr 5;102(14):5221-6. Epub 2005 Mar 22. (
  • Namboodiri AM, Peethambaran A, Mathew R, Sambhu PA, Hershfield J, Moffett JR, Madhavarao CN. Canavan disease and the role of N-acetylaspartate in myelin synthesis. Mol Cell Endocrinol. 2006 Jun 27;252(1-2):216-23. Epub 2006 May 2. Review. (
  • NCBI Gene (
  • Sommer A, Sass JO. Expression of aspartoacylase (ASPA) and Canavan disease. Gene. 2012 Sep 1;505(2):206-10. doi: 10.1016/j.gene.2012.06.036. Epub 2012 Jun 28. (
  • Tacke U, Olbrich H, Sass JO, Fekete A, Horvath J, Ziyeh S, Kleijer WJ, Rolland MO, Fisher S, Payne S, Vargiami E, Zafeiriou DI, Omran H. Possible genotype-phenotype correlations in children with mild clinical course of Canavan disease. Neuropediatrics. 2005 Aug;36(4):252-5. (
  • Zano S, Wijayasinghe YS, Malik R, Smith J, Viola RE. Relationship between enzyme properties and disease progression in Canavan disease. J Inherit Metab Dis. 2013 Jan;36(1):1-6. doi: 10.1007/s10545-012-9520-z. Epub 2012 Aug 1. Erratum in: J Inherit Metab Dis. 2013 Jan;36(1):159-60. (
  • Zeng BJ, Pastores GM, Leone P, Raghavan S, Wang ZH, Ribeiro LA, Torres P, Ong E, Kolodny EH. Mutation analysis of the aspartoacylase gene in non-Jewish patients with Canavan disease. Adv Exp Med Biol. 2006;576:165-73; discussion 361-3. (
  • Zeng BJ, Wang ZH, Torres PA, Pastores GM, Leone P, Raghavan SS, Kolodny EH. Rapid detection of three large novel deletions of the aspartoacylase gene in non-Jewish patients with Canavan disease. Mol Genet Metab. 2006 Sep-Oct;89(1-2):156-63. Epub 2006 Jul 18. (


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: January 2008
Published: March 23, 2015