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NAGLU gene


Normal Function

The NAGLU gene provides instructions for producing an enzyme called alpha-N-acetylglucosaminidase. This enzyme is located in lysosomes, compartments within cells that digest and recycle different types of molecules. Alpha-N-acetylglucosaminidase is involved in the step-wise breakdown 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. Alpha-N-acetylglucosaminidase removes a sugar called N-acetylglucosamine when it is at the end of the GAG chain.

Health Conditions Related to Genetic Changes

Mucopolysaccharidosis type III

At least 118 mutations in the NAGLU gene have been found to cause mucopolysaccharidosis type IIIB (MPS IIIB). Most of these mutations change single DNA building blocks (nucleotides) in the gene. All of the mutations that cause MPS IIIB reduce or eliminate the function of alpha-N-acetylglucosaminidase.

The lack of alpha-N-acetylglucosaminidase activity disrupts the breakdown of a subset of GAGs called 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 IIIB.

More About This Health Condition

Charcot-Marie-Tooth disease

MedlinePlus Genetics provides information about Charcot-Marie-Tooth disease

More About This Health Condition

Other Names for This Gene

  • alpha-N-acetylglucosaminidase
  • alpha-N-acetylglucosaminidase precursor
  • N-acetylglucosaminidase, alpha
  • N-acetylglucosaminidase, alpha-
  • NAG

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Beesley CE, Jackson M, Young EP, Vellodi A, Winchester BG. Molecular defects in Sanfilippo syndrome type B (mucopolysaccharidosis IIIB). J Inherit Metab Dis. 2005;28(5):759-67. doi: 10.1007/s10545-005-0093-y. Citation on PubMed
  • Ficko-Blean E, Stubbs KA, Nemirovsky O, Vocadlo DJ, Boraston AB. Structural and mechanistic insight into the basis of mucopolysaccharidosis IIIB. Proc Natl Acad Sci U S A. 2008 May 6;105(18):6560-5. doi: 10.1073/pnas.0711491105. Epub 2008 Apr 28. Citation on PubMed or Free article on PubMed Central
  • Ohmi K, Kudo LC, Ryazantsev S, Zhao HZ, Karsten SL, Neufeld EF. Sanfilippo syndrome type B, a lysosomal storage disease, is also a tauopathy. Proc Natl Acad Sci U S A. 2009 May 19;106(20):8332-7. doi: 10.1073/pnas.0903223106. Epub 2009 May 5. Citation on PubMed or Free article on PubMed Central
  • 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. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.