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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.
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.
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.
Cytogenetic Location: 3p21
Molecular Location on chromosome 3: base pairs 50,191,610 to 50,197,696
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 50,191,610 to base pair 50,197,696 on chromosome 3.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
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.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
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.
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.