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


Reviewed August 2010

What is the official name of the HGSNAT gene?

The official name of this gene is “heparan-alpha-glucosaminide N-acetyltransferase.”

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

What is the normal function of the HGSNAT gene?

The HGSNAT gene provides instructions for producing an enzyme called heparan-alpha-glucosaminide N-acetyltransferase (which is often shortened to N-acetyltransferase). This enzyme is located in lysosomes, compartments within cells that digest and recycle different types of molecules. N-acetyltransferase is involved in the step-wise breakdown (degradation) of large molecules called glycosaminoglycans (GAGs). GAGs are composed of sugar molecules that are linked together to form a long string. To break down these large molecules, individual sugars are removed one at a time from one end of the molecule. N-acetyltransferase adds a molecule called an acetyl group to the sugar glucosamine in a subset of GAGs called heparan sulfate. This addition prepares the GAG for the next step in the degradation process.

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

mucopolysaccharidosis type III - caused by mutations in the HGSNAT gene

At least 54 mutations in the HGSNAT gene have been found to cause mucopolysaccharidosis type IIIC (MPS IIIC). Most of these mutations change single DNA building blocks (nucleotides) in the gene. All of the mutations that cause MPS IIIC reduce or eliminate the function of N-acetyltransferase.

The lack of N-acetyltransferase activity disrupts the breakdown of heparan sulfate. As a result, partially broken down heparan sulfate accumulates within lysosomes. Researchers believe that the accumulation of GAGs interferes with the functions of other proteins inside the lysosomes and disrupts the normal functions of cells. It is unknown why the buildup of heparan sulfate mostly affects the central nervous system in MPS IIIC.

Where is the HGSNAT gene located?

Cytogenetic Location: 8p11.1

Molecular Location on chromosome 8: base pairs 43,140,449 to 43,202,827

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The HGSNAT gene is located on the short (p) arm of chromosome 8 at position 11.1.

The HGSNAT gene is located on the short (p) arm of chromosome 8 at position 11.1.

More precisely, the HGSNAT gene is located from base pair 43,140,449 to base pair 43,202,827 on chromosome 8.

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

Where can I find additional information about HGSNAT?

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

  • acetyl coenzyme A:alpha-glucosaminide N-acetyltransferase
  • DKFZp686G24175
  • FLJ22242
  • FLJ32731
  • TMEM76
  • transmembrane protein 76

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

What glossary definitions help with understanding HGSNAT?

breakdown ; central nervous system ; coenzyme A ; degradation ; DNA ; enzyme ; gene ; heparan sulfate ; molecule ; nervous system ; protein ; sulfate ; transmembrane

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


  • Fan X, Zhang H, Zhang S, Bagshaw RD, Tropak MB, Callahan JW, Mahuran DJ. Identification of the gene encoding the enzyme deficient in mucopolysaccharidosis IIIC (Sanfilippo disease type C). Am J Hum Genet. 2006 Oct;79(4):738-44. Epub 2006 Aug 23. (
  • Feldhammer M, Durand S, Mrázová L, Boucher RM, Laframboise R, Steinfeld R, Wraith JE, Michelakakis H, van Diggelen OP, Hrebícek M, Kmoch S, Pshezhetsky AV. Sanfilippo syndrome type C: mutation spectrum in the heparan sulfate acetyl-CoA: alpha-glucosaminide N-acetyltransferase (HGSNAT) gene. Hum Mutat. 2009 Jun;30(6):918-25. doi: 10.1002/humu.20986. Review. (
  • Feldhammer M, Durand S, Pshezhetsky AV. Protein misfolding as an underlying molecular defect in mucopolysaccharidosis III type C. PLoS One. 2009 Oct 13;4(10):e7434. doi: 10.1371/journal.pone.0007434. (
  • Hrebícek M, Mrázová L, Seyrantepe V, Durand S, Roslin NM, Nosková L, Hartmannová H, Ivánek R, Cízkova A, Poupetová H, Sikora J, Urinovská J, Stranecký V, Zeman J, Lepage P, Roquis D, Verner A, Ausseil J, Beesley CE, Maire I, Poorthuis BJ, van de Kamp J, van Diggelen OP, Wevers RA, Hudson TJ, Fujiwara TM, Majewski J, Morgan K, Kmoch S, Pshezhetsky AV. Mutations in TMEM76* cause mucopolysaccharidosis IIIC (Sanfilippo C syndrome). Am J Hum Genet. 2006 Nov;79(5):807-19. Epub 2006 Sep 8. (
  • NCBI Gene (
  • Ruijter GJ, Valstar MJ, van de Kamp JM, van der Helm RM, Durand S, van Diggelen OP, Wevers RA, Poorthuis BJ, Pshezhetsky AV, Wijburg FA. Clinical and genetic spectrum of Sanfilippo type C (MPS IIIC) disease in The Netherlands. Mol Genet Metab. 2008 Feb;93(2):104-11. Epub 2007 Nov 19. (
  • Valstar MJ, Ruijter GJ, van Diggelen OP, Poorthuis BJ, Wijburg FA. Sanfilippo syndrome: a mini-review. J Inherit Metab Dis. 2008 Apr;31(2):240-52. doi: 10.1007/s10545-008-0838-5. Epub 2008 Apr 4. Review. (


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: August 2010
Published: February 1, 2016