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

GR gene family

Reviewed January 2014

What are the GR genes?

The GR gene family provides instructions for making proteins called glutamate receptors. These proteins are found on the surface of cells, most frequently nerve cells (neurons), where they attach (bind) to a molecule called glutamate and control its activity. Glutamate is one of several chemicals called neurotransmitters, which allow neurons to communicate with one another.

Cells use glutamate to communicate by transferring this molecule from one cell to another with the help of glutamate receptors. During cell signaling, one cell releases glutamate, which is taken up by a neighboring cell by binding to its glutamate receptor. This binding triggers signaling within the receiving cell. After glutamate has had the intended signaling effect, the glutamate receptor releases it to be reused.

There are two forms of glutamate receptors: metabotropic and ionotropic. These forms are distinguished by their structure and how they relay signals to the cell. When a metabotropic glutamate receptor (mGlu) binds to glutamate, the receptor is turned on (activated) and sends a signal to the cell. When an ionotropic glutamate receptor (iGlu) binds to glutamate, the receptor opens up, allowing charged atoms (ions) to flow into the cell, which causes signaling within the cell.

Mutations in GR genes can alter the way signals are sent between cells and often play a role in the development of neurological conditions such as recurrent seizures (epilepsy), mood disorders, and schizophrenia. Some GR gene mutations impair other body systems; for example, mutations in the GRM6 gene causes a condition called autosomal recessive congenital stationary night blindness, which is characterized by an inability to see in low-light.

Which genes are included in the GR gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides an index of gene families ( and their member genes.

Genetics Home Reference summarizes the normal function and health implications of this member of the GR gene family: GRM6.

What conditions are related to genes in the GR gene family?

Genetics Home Reference includes these conditions related to genes in the GR gene family:

  • autosomal recessive congenital stationary night blindness

Where can I find additional information about the GR gene family?

You may find the following resources about the GR gene family helpful.

  • Basic Neurochemistry (sixth edition, 1999): Three Classes of Ionotropic Glutamate Receptor ( (U.S. National Library of Medicine)
  • Jasper's Basic Mechanisms of the Epilepsies (fourth edition, 2012): Glutamate Receptor Structure ( (U.S. National Library of Medicine)
  • Neuroscience (second edition, 2001): Glutamate Receptors ( (U.S. National Library of Medicine)
  • Basic Neurochemistry (sixth edition, 1999): Metabotropic Receptors Modulate Synaptic Transmission ( (U.S. National Library of Medicine)
  • Jasper's Basic Mechanisms of the Epilepsies (fourth edition, 2012): Glutamate Receptors ( (U.S. National Library of Medicine)

What glossary definitions help with understanding the GR gene family?

autosomal ; autosomal recessive ; cell ; congenital ; epilepsy ; gene ; ions ; molecule ; neurological ; neurotransmitters ; receptor ; recessive ; schizophrenia

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


These sources were used to develop the Genetics Home Reference summary for the GR gene family.

  • Sheffler DJ, Gregory KJ, Rook JM, Conn PJ. Allosteric modulation of metabotropic glutamate receptors. Adv Pharmacol. 2011;62:37-77. doi: 10.1016/B978-0-12-385952-5.00010-5. Review. (
  • Willard SS, Koochekpour S. Glutamate, glutamate receptors, and downstream signaling pathways. Int J Biol Sci. 2013 Sep 22;9(9):948-59. doi: 10.7150/ijbs.6426. eCollection 2013. Review. (
  • Niswender CM, Conn PJ. Metabotropic glutamate receptors: physiology, pharmacology, and disease. Annu Rev Pharmacol Toxicol. 2010;50:295-322. doi: 10.1146/annurev.pharmtox.011008.145533. Review. (
  • Kaczor AA, Matosiuk D. Molecular structure of ionotropic glutamate receptors. Curr Med Chem. 2010;17(24):2608-35. Review. (
  • Stawski P, Janovjak H, Trauner D. Pharmacology of ionotropic glutamate receptors: A structural perspective. Bioorg Med Chem. 2010 Nov 15;18(22):7759-72. doi: 10.1016/j.bmc.2010.09.012. Epub 2010 Sep 19. Review. (
  • Nicoletti F, Bockaert J, Collingridge GL, Conn PJ, Ferraguti F, Schoepp DD, Wroblewski JT, Pin JP. Metabotropic glutamate receptors: from the workbench to the bedside. Neuropharmacology. 2011 Jun;60(7-8):1017-41. doi: 10.1016/j.neuropharm.2010.10.022. Epub 2010 Oct 29. Review. (
  • Sobolevsky AI. Structure and gating of tetrameric glutamate receptors. J Physiol. 2015 Jan 1;593(1):29-38. doi: 10.1113/jphysiol.2013.264911. Epub 2013 Nov 25. 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: January 2014
Published: February 1, 2016