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The official name of this gene is “guanine nucleotide binding protein (G protein), alpha transducing activity polypeptide 2.”
GNAT2 is the gene's official symbol. The GNAT2 gene is also known by other names, listed below.
The GNAT2 gene provides instructions for making one part (the alpha subunit) of a protein called transducin. This protein, which is necessary for normal vision, is present in light receptor cells called cones. As part of the light-sensitive tissue at the back of the eye (the retina), cones provide vision in bright light, including color vision. Other light receptor cells in the retina, called rods, are responsible for vision in low light.
Transducin plays an essential role in transmitting visual signals from cones in the retina to the brain. Three types of cones each contain a special pigment (a photopigment) that is most sensitive to a particular wavelength of light. When any of the three photopigments absorbs light, it activates the transducin protein. Transducin then triggers a series of chemical reactions within a cone cell. These reactions ultimately alter the cell's electrical charge, generating a signal that the brain interprets as vision.
Fewer than 10 mutations in the GNAT2 gene have been identified in people with color vision deficiency. These mutations typically cause complete achromatopsia, which is a loss of all color vision. Each of the reported GNAT2 mutations leads to an abnormally small, nonfunctional version of the GNAT2 protein. This altered protein either prevents the assembly of transducin or disrupts transducin's interaction with photopigments. As a result, cones are unable to transmit visual signals to the brain. A loss of normal cone function causes a lack of color vision, reduced sharpness, and other vision problems associated with complete achromatopsia.
Cytogenetic Location: 1p13.1
Molecular Location on chromosome 1: base pairs 109,603,266 to 109,613,082
The GNAT2 gene is located on the short (p) arm of chromosome 1 at position 13.1.
More precisely, the GNAT2 gene is located from base pair 109,603,266 to base pair 109,613,082 on chromosome 1.
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 GNAT2 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.
achromatopsia ; cell ; cone cell ; cones ; deficiency ; gene ; guanine ; nucleotide ; photopigment ; pigment ; protein ; receptor ; retina ; 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).
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.