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Genetics Home Reference: your guide to understanding genetic conditions
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GNPTG

Reviewed August 2009

What is the official name of the GNPTG gene?

The official name of this gene is “N-acetylglucosamine-1-phosphate transferase, gamma subunit.”

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

What is the normal function of the GNPTG gene?

The GNPTG gene provides instructions for making one part, the gamma subunit, of an enzyme called GlcNAc-1-phosphotransferase. This enzyme is made up of two alpha (α), two beta (β), and two gamma (γ) subunits. The alpha and beta subunits are produced from a different gene, called GNPTAB. GlcNAc-1-phosphotransferase helps prepare certain newly made enzymes for transport to lysosomes. Lysosomes are compartments within the cell that use digestive enzymes called hydrolases to break down large molecules into smaller ones that can be reused by cells.

GlcNAc-1-phosphotransferase is involved in the first step of making a molecule called mannose-6-phosphate (M6P). M6P acts as a tag that indicates a hydrolase should be transported to the lysosome. Specifically, GlcNAc-1-phosphotransferase transfers a molecule called GlcNac-1-phosphate to a newly produced hydrolase. In the next step, a molecule is removed to reveal an M6P attached to the hydrolase. Once a hydrolase has an M6P tag, it can be transported to a lysosome.

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

mucolipidosis III gamma - caused by mutations in the GNPTG gene

At least 8 mutations in the GNPTG gene have been found to cause mucolipidosis III gamma. These mutations result in reduced the activity of GlcNAc-1-phosphotransferase, which disrupts tagging of hydrolases with M6P. Digestive enzymes that do not receive the M6P tag end up outside the cell, where they have increased activity. The shortage of these digestive enzymes within lysosomes causes large molecules to accumulate there. Conditions that cause molecules to build up inside lysosomes, including mucolipidosis III gamma, are called lysosomal storage disorders. The signs and symptoms of mucolipidosis III gamma are most likely due to the shortage of hydrolases inside lysosomes and the effects these enzymes have outside the cell.

Where is the GNPTG gene located?

Cytogenetic Location: 16p13.3

Molecular Location on chromosome 16: base pairs 1,351,898 to 1,363,350

The GNPTG gene is located on the short (p) arm of chromosome 16 at position 13.3.

The GNPTG gene is located on the short (p) arm of chromosome 16 at position 13.3.

More precisely, the GNPTG gene is located from base pair 1,351,898 to base pair 1,363,350 on chromosome 16.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about GNPTG?

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

  • C16orf27
  • c316G12.3
  • CAB56184
  • GlcNAc-phosphotransferase gamma-subunit
  • GNPTAG
  • GNPTG_HUMAN
  • LP2537
  • N-acetylglucosamine-1-phosphotransferase, gamma subunit
  • RJD9

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding GNPTG?

cell ; digestive ; enzyme ; gene ; hydrolase ; lysosome ; mannose ; molecule ; phosphate ; subunit ; transferase

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • OMIM: N-ACETYLGLUCOSAMINE-1-PHOSPHOTRANSFERASE, GAMMA SUBUNIT (http://omim.org/entry/607838)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/84572)
  • Persichetti E, Chuzhanova NA, Dardis A, Tappino B, Pohl S, Thomas NS, Rosano C, Balducci C, Paciotti S, Dominissini S, Montalvo AL, Sibilio M, Parini R, Rigoldi M, Di Rocco M, Parenti G, Orlacchio A, Bembi B, Cooper DN, Filocamo M, Beccari T. Identification and molecular characterization of six novel mutations in the UDP-N-acetylglucosamine-1-phosphotransferase gamma subunit (GNPTG) gene in patients with mucolipidosis III gamma. Hum Mutat. 2009 Jun;30(6):978-84. doi: 10.1002/humu.20959. (http://www.ncbi.nlm.nih.gov/pubmed/19370764?dopt=Abstract)
  • Pohl S, Tiede S, Castrichini M, Cantz M, Gieselmann V, Braulke T. Compensatory expression of human N-acetylglucosaminyl-1-phosphotransferase subunits in mucolipidosis type III gamma. Biochim Biophys Acta. 2009 Mar;1792(3):221-5. doi: 10.1016/j.bbadis.2009.01.009. (http://www.ncbi.nlm.nih.gov/pubmed/19708128?dopt=Abstract)
  • Raas-Rothschild A, Bargal R, Goldman O, Ben-Asher E, Groener JE, Toutain A, Stemmer E, Ben-Neriah Z, Flusser H, Beemer FA, Penttinen M, Olender T, Rein AJ, Bach G, Zeigler M. Genomic organisation of the UDP-N-acetylglucosamine-1-phosphotransferase gamma subunit (GNPTAG) and its mutations in mucolipidosis III. J Med Genet. 2004 Apr;41(4):e52. (http://www.ncbi.nlm.nih.gov/pubmed/15060128?dopt=Abstract)
  • Raas-Rothschild A, Cormier-Daire V, Bao M, Genin E, Salomon R, Brewer K, Zeigler M, Mandel H, Toth S, Roe B, Munnich A, Canfield WM. Molecular basis of variant pseudo-hurler polydystrophy (mucolipidosis IIIC). J Clin Invest. 2000 Mar;105(5):673-81. (http://www.ncbi.nlm.nih.gov/pubmed/10712439?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: August 2009
Published: December 22, 2014