Reviewed February 2006
What is the official name of the COL4A3 gene?
The official name of this gene is “collagen, type IV, alpha 3 (Goodpasture antigen).”
COL4A3 is the gene's official symbol. The COL4A3 gene is also known by other names, listed below.
What is the normal function of the COL4A3 gene?
The COL4A3 gene carries the instructions for making one component of type IV collagen, which is a flexible protein that forms complex networks. Specifically, this gene makes the alpha3(IV) chain of type IV collagen. This chain combines with two other types of alpha (IV) chains (the alpha4 and alpha5 chains) to make a complete collagen molecule. Type IV collagen networks make up a large portion of basement membranes, which are thin sheet-like structures that separate and support cells in many tissues. This specific type IV collagen network plays an especially important role in the basement membranes of the kidney, inner ear, and eye.
How are changes in the COL4A3 gene related to health conditions?
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Alport syndrome - caused by mutations in the COL4A3 gene
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The autosomal recessive form of Alport syndrome results when two copies of the COL4A3 gene in each cell are mutated. Most of the mutations identified in this gene cause a change in the sequence of amino acids (the building blocks of proteins) in a region of the alpha3(IV) collagen chain that is critical for combining with other type IV collagen chains. Other mutations severely decrease or prevent the production of any alpha3(IV) chains in the basement membranes of the kidney, inner ear and eye. In the kidney, other types of collagen accumulate in the basement membranes, eventually leading to scarring of the kidneys and kidney failure. Mutations in this gene can also lead to abnormal function in the inner ear, resulting in hearing loss.
- other disorders - associated with the COL4A3 gene
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Thin basement membrane nephropathy is an autosomal dominant condition, which means one copy of the altered COL4A3 gene in each cell is sufficient to cause the disorder. In the past, this condition was often called benign familial hematuria. People with thin basement membrane nephropathy typically have blood in their urine but no other symptoms or signs of kidney disease, and it is unusual for this condition to lead to kidney failure.
Goodpasture syndrome is a severe disease of the lungs and the kidneys caused by antibodies to the alpha3(IV) collagen chains. Antibodies, which are part of the immune system, are proteins that normally attack foreign substances such as bacteria or viruses. It remains unclear why some people make antibodies to their own collagen chains. The antibody binds to the basement membranes of blood vessels in the alveoli (air sacs) of the lungs and glomeruli (filtering units) of the kidneys. Binding of antibody to these structures causes inflammation, leading to bleeding in the lungs (people with this condition may cough up blood) and kidney failure.
In some people, antibodies attack only the kidneys. These people are said to have anti-glomerular basement membrane nephritis.
Where is the COL4A3 gene located?
Cytogenetic Location: 2q36-q37
Molecular Location on chromosome 2: base pairs 227,737,524 to 227,887,750
The COL4A3 gene is located on the long (q) arm of chromosome 2 between positions 36 and 37.
More precisely, the COL4A3 gene is located from base pair 227,737,524 to base pair 227,887,750 on chromosome 2.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about COL4A3?
You and your healthcare professional may find the following resources about COL4A3 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
- PubMed
- Recent literature
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OMIM - Genetic disorder catalog (3 links)
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What other names do people use for the COL4A3 gene or gene products?
- CO4A3_HUMAN
- collagen IV, alpha-3 polypeptide
- Goodpasture antigen
- TUMSTATIN
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding COL4A3?
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.