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Normal Function
The GRM6 gene provides instructions for making a protein called metabotropic glutamate receptor 6 (mGluR6). This protein is a glutamate receptor, which is a type of protein that attaches (binds) to the signaling molecule glutamate on the surface of cells. The mGluR6 protein is found within the membrane that surrounds cells called bipolar cells, which are part of the light-sensitive tissue at the back of the eye (retina). Bipolar cells receive visual signals from cells called rods that are used to see in low light. Rod cells release glutamate, which then binds to mGluR6 on bipolar cells. This binding ultimately triggers bipolar cells to transmit the visual signals to other retinal cells and eventually to the brain.
Health Conditions Related to Genetic Changes
Autosomal recessive congenital stationary night blindness
At least 25 mutations in the GRM6 gene have been found to cause autosomal recessive congenital stationary night blindness, which is characterized by the inability to see in low light and other vision problems such as nearsightedness (myopia).
Most GRM6 gene mutations impair the function of the mGluR6 protein by changing single protein building blocks (amino acids) in the protein. These mutations prevent the protein from reaching the cell membrane where it is needed to bind to glutamate. Without any mGluR6 protein at the cell surface, the glutamate released from rod cells in low light is not detected by bipolar cells, so visual signals are not transmitted. The brain does not receive the visual information sent by rods, leading to difficulty seeing in low light.
More About This Health ConditionOther Names for This Gene
- glutamate receptor, metabotropic 6
- GPRC1F
- GRM6_HUMAN
- metabotropic glutamate receptor 6
- mGlu6
- MGLUR6
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Beqollari D, Betzenhauser MJ, Kammermeier PJ. Altered G-protein coupling in an mGluR6 point mutant associated with congenital stationary night blindness. Mol Pharmacol. 2009 Nov;76(5):992-7. doi: 10.1124/mol.109.058628. Epub 2009 Aug 7. Citation on PubMed
- Dryja TP, McGee TL, Berson EL, Fishman GA, Sandberg MA, Alexander KR, Derlacki DJ, Rajagopalan AS. Night blindness and abnormal cone electroretinogram ON responses in patients with mutations in the GRM6 gene encoding mGluR6. Proc Natl Acad Sci U S A. 2005 Mar 29;102(13):4884-9. doi: 10.1073/pnas.0501233102. Epub 2005 Mar 21. Citation on PubMed or Free article on PubMed Central
- Sergouniotis PI, Robson AG, Li Z, Devery S, Holder GE, Moore AT, Webster AR. A phenotypic study of congenital stationary night blindness (CSNB) associated with mutations in the GRM6 gene. Acta Ophthalmol. 2012 May;90(3):e192-7. doi: 10.1111/j.1755-3768.2011.02267.x. Epub 2011 Oct 19. Citation on PubMed
- Wang Q, Gao Y, Li S, Guo X, Zhang Q. Mutation screening of TRPM1, GRM6, NYX and CACNA1F genes in patients with congenital stationary night blindness. Int J Mol Med. 2012 Sep;30(3):521-6. doi: 10.3892/ijmm.2012.1039. Epub 2012 Jun 20. Citation on PubMed
- Zeitz C, Forster U, Neidhardt J, Feil S, Kalin S, Leifert D, Flor PJ, Berger W. Night blindness-associated mutations in the ligand-binding, cysteine-rich, and intracellular domains of the metabotropic glutamate receptor 6 abolish protein trafficking. Hum Mutat. 2007 Aug;28(8):771-80. doi: 10.1002/humu.20499. Citation on PubMed
- Zeitz C, van Genderen M, Neidhardt J, Luhmann UF, Hoeben F, Forster U, Wycisk K, Matyas G, Hoyng CB, Riemslag F, Meire F, Cremers FP, Berger W. Mutations in GRM6 cause autosomal recessive congenital stationary night blindness with a distinctive scotopic 15-Hz flicker electroretinogram. Invest Ophthalmol Vis Sci. 2005 Nov;46(11):4328-35. doi: 10.1167/iovs.05-0526. Citation on PubMed
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