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COG5 gene

component of oligomeric golgi complex 5

Normal Function

The COG5 gene provides instructions for making a protein called component of oligomeric Golgi complex 5 (COG5). As its name suggests, COG5 is one piece of a group of proteins known as the conserved oligomeric Golgi (COG) complex. This complex functions in the Golgi apparatus, which is a cell structure in which newly produced proteins are modified. One process that occurs in the Golgi apparatus is glycosylation, by which sugar molecules (oligosaccharides) are attached to proteins and fats. Glycosylation modifies proteins so they can perform a wider variety of functions.

The COG complex takes part in the transport of proteins, including the enzymes that perform glycosylation, within the Golgi apparatus. COG is specifically involved in retrograde transport, which moves proteins backward through the Golgi apparatus. Retrograde transport is important for recycling Golgi proteins and ensuring that they are in the correct location in the structure, which is key to proper glycosylation. The proteins are transported in sac-like structures called vesicles that attach to the Golgi membrane and release the contents into the Golgi apparatus. The COG complex controls the attachment (tethering) of the vesicles to the Golgi membrane.

Health Conditions Related to Genetic Changes

COG5-congenital disorder of glycosylation

At least eight mutations in the COG5 gene are known to cause COG5-congenital disorder of glycosylation (COG5-CDG). This condition often leads to developmental delay and intellectual disability and causes other abnormalities. Mutations in the COG5 gene reduce the amount of COG5 protein or eliminate it completely, which disrupts retrograde transport in the Golgi apparatus. This disruption results in abnormal protein glycosylation, which can affect multiple body systems, leading to the signs and symptoms of COG5-CDG. The severity of the condition is related to the amount of COG5 protein that remains in cells.

More About This Health Condition

Other Names for This Gene

  • 13S golgi transport complex 1 90 kDa subunit
  • CDG2I
  • COG complex subunit 5
  • conserved oligomeric Golgi complex protein 5
  • conserved oligomeric Golgi complex subunit 5
  • GOLTC1
  • GTC90

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


  • Fung CW, Matthijs G, Sturiale L, Garozzo D, Wong KY, Wong R, Wong V, Jaeken J. COG5-CDG with a Mild Neurohepatic Presentation. JIMD Rep. 2012;3:67-70. doi: 10.1007/8904_2011_61. Epub 2011 Sep 22. Citation on PubMed or Free article on PubMed Central
  • Miller VJ, Sharma P, Kudlyk TA, Frost L, Rofe AP, Watson IJ, Duden R, Lowe M, Lupashin VV, Ungar D. Molecular insights into vesicle tethering at the Golgi by the conserved oligomeric Golgi (COG) complex and the golgin TATA element modulatory factor (TMF). J Biol Chem. 2013 Feb 8;288(6):4229-40. doi: 10.1074/jbc.M112.426767. Epub 2012 Dec 13. Citation on PubMed or Free article on PubMed Central
  • Oka T, Vasile E, Penman M, Novina CD, Dykxhoorn DM, Ungar D, Hughson FM, Krieger M. Genetic analysis of the subunit organization and function of the conserved oligomeric golgi (COG) complex: studies of COG5- and COG7-deficient mammalian cells. J Biol Chem. 2005 Sep 23;280(38):32736-45. doi: 10.1074/jbc.M505558200. Epub 2005 Jul 28. Citation on PubMed
  • Reynders E, Foulquier F, Annaert W, Matthijs G. How Golgi glycosylation meets and needs trafficking: the case of the COG complex. Glycobiology. 2011 Jul;21(7):853-63. doi: 10.1093/glycob/cwq179. Epub 2010 Nov 26. Citation on PubMed
  • Rymen D, Keldermans L, Race V, Regal L, Deconinck N, Dionisi-Vici C, Fung CW, Sturiale L, Rosnoblet C, Foulquier F, Matthijs G, Jaeken J. COG5-CDG: expanding the clinical spectrum. Orphanet J Rare Dis. 2012 Dec 10;7:94. doi: 10.1186/1750-1172-7-94. Erratum In: Orphanet J Rare Dis. 2013;8:120. Citation on PubMed or Free article on PubMed Central
  • Smith RD, Lupashin VV. Role of the conserved oligomeric Golgi (COG) complex in protein glycosylation. Carbohydr Res. 2008 Aug 11;343(12):2024-31. doi: 10.1016/j.carres.2008.01.034. Epub 2008 Feb 2. Citation on PubMed or Free article on PubMed Central

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.