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Genetics Home Reference: your guide to understanding genetic conditions
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GNAT1

Reviewed November 2013

What is the official name of the GNAT1 gene?

The official name of this gene is “guanine nucleotide binding protein (G protein), alpha transducing activity polypeptide 1.”

GNAT1 is the gene's official symbol. The GNAT1 gene is also known by other names, listed below.

What is the normal function of the GNAT1 gene?

The GNAT1 gene provides instructions for making a protein called alpha (α)-transducin. This protein is one part (the alpha subunit) of a protein complex called transducin. There are several versions of transducin made up of different subunits. Each version is found in a particular cell type in the light-sensitive tissue at the back of the eye (the retina), where it plays a role in transmitting visual signals from the eye to the brain.

The transducin complex that contains α-transducin is found only in specialized light receptor cells in the retina called rods. Rods are responsible for vision in low-light conditions. When light enters the eye, a rod cell protein called rhodopsin is turned on (activated), which then activates α-transducin. Once activated, α-transducin breaks away from the transducin complex in order to activate another protein called cGMP-PDE, which triggers a series of chemical reactions that create electrical signals. These signals are transmitted from rod cells to the brain, where they are interpreted as vision.

How are changes in the GNAT1 gene related to health conditions?

autosomal dominant congenital stationary night blindness - caused by mutations in the GNAT1 gene

At least two mutations in the GNAT1 gene have been found to cause autosomal dominant congenital stationary night blindness, which is characterized by the inability to see in low light.

One of these mutations impairs the protein's ability to activate cGMP-PDE; the other mutation results in a protein that is constantly turned on (constitutively activated). Both of these mutations disrupt the pathway that creates visual signals to be sent from rod cells to the brain. A nonfunctional α-transducin protein stops the signaling pathway. When α-transducin is constitutively activated, the signals that the rod cells send to the brain are constantly occurring, even in bright light. Visual information from rod cells is then perceived by the brain as not meaningful, resulting in night blindness.

Where is the GNAT1 gene located?

Cytogenetic Location: 3p21

Molecular Location on chromosome 3: base pairs 50,191,609 to 50,197,695

The GNAT1 gene is located on the short (p) arm of chromosome 3 at position 21.

The GNAT1 gene is located on the short (p) arm of chromosome 3 at position 21.

More precisely, the GNAT1 gene is located from base pair 50,191,609 to base pair 50,197,695 on chromosome 3.

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 GNAT1?

You and your healthcare professional may find the following resources about GNAT1 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 GNAT1 gene or gene products?

  • CSNBAD3
  • GBT1
  • GNAT1_HUMAN
  • GNATR
  • guanine nucleotide-binding protein G(T), alpha-1 subunit
  • guanine nucleotide-binding protein G(t) subunit alpha-1
  • rod-type transducin alpha subunit
  • transducin alpha-1 chain
  • transducin, rod-specific

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 GNAT1?

autosomal ; autosomal dominant ; cell ; congenital ; gene ; guanine ; mutation ; nucleotide ; photoreceptor ; protein ; receptor ; retina ; rod cell ; rods ; subunit ; tissue

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

References

  • Dryja TP, Hahn LB, Reboul T, Arnaud B. Missense mutation in the gene encoding the alpha subunit of rod transducin in the Nougaret form of congenital stationary night blindness. Nat Genet. 1996 Jul;13(3):358-60. (http://www.ncbi.nlm.nih.gov/pubmed/8673138?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/2779)
  • OMIM: GUANINE NUCLEOTIDE-BINDING PROTEIN, ALPHA-TRANSDUCING ACTIVITY POLYPEPTIDE 1 (http://omim.org/entry/139330)
  • Sandberg MA, Pawlyk BS, Dan J, Arnaud B, Dryja TP, Berson EL. Rod and cone function in the Nougaret form of stationary night blindness. Arch Ophthalmol. 1998 Jul;116(7):867-72. (http://www.ncbi.nlm.nih.gov/pubmed/9682699?dopt=Abstract)
  • Szabo V, Kreienkamp HJ, Rosenberg T, Gal A. p.Gln200Glu, a putative constitutively active mutant of rod alpha-transducin (GNAT1) in autosomal dominant congenital stationary night blindness. Hum Mutat. 2007 Jul;28(7):741-2. (http://www.ncbi.nlm.nih.gov/pubmed/17584859?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: November 2013
Published: July 21, 2014