The COL6A3 gene provides instructions for making one component of type VI collagen, which is a flexible protein found in the space that surrounds cells. Specifically, the protein produced from the COL6A3 gene is the alpha(α)3(VI) chain of type VI collagen. This chain combines with chains produced from other genes to produce a complete type VI collagen molecule.
Collagens are found in the extracellular matrix, which is an intricate lattice that forms in the space between cells and provides structural support. Type VI collagen is located in the extracellular matrix surrounding cells that make up the muscles used for movement (skeletal muscle cells) and cells that make up connective tissue, which provides strength and flexibility to structures throughout the body, including skin and joints. The extracellular matrix is necessary for cell stability and growth. Research suggests that type VI collagen links basement membranes, which are thin, sheet-like structures that are part of the extracellular matrix, to nearby cells.
Health Conditions Related to Genetic Changes
Collagen VI-related dystrophy
Variants (also known as mutations) in the COL6A3 gene have been found to cause some cases of collagen VI-related dystrophy, which is a group of disorders that vary in severity but generally result in muscle weakness and joint deformities called contractures. These variants often change single protein building blocks (amino acids) in the α3(VI) chain. The most frequently affected amino acid is glycine; changes to this building block disrupt the structure of the α3(VI) chain. Other variants can also disrupt the structure of the α3(VI) chain.
Variants in the COL6A3 gene affect type VI collagen in different ways. Some variants lead to altered α3(VI) chains that can be incorporated into the mature type VI collagen molecule, although they disrupt the molecule's structure and function. Other variants result in an altered chain that cannot be incorporated at all. Still other variants prevent the production of any functional α3(VI) chain, which impedes formation of type VI collagen. All of these COL6A3 gene variants lead to a reduction or absence of functional collagen VI molecules. While it is difficult to predict the severity of collagen VI-related dystrophy based on the type of variant, in general, lower amounts of type VI collagen lead to more severe signs and symptoms that begin earlier in life.
Changes in α3(VI) chain structure or production lead to an unstable extracellular matrix that is no longer attached to cells through the basement membrane. As a result, the stability of muscle cells and connective tissue progressively declines, which leads to the muscle weakness, contractures, and other signs and symptoms of collagen VI-related dystrophy.More About This Health Condition
Limb-girdle muscular dystrophy
MedlinePlus Genetics provides information about Limb-girdle muscular dystrophyMore About This Health Condition
Other Names for This Gene
- collagen alpha-3(VI) chain
- collagen type VI alpha 3
- collagen VI, alpha-3 polypeptide
- collagen, type VI, alpha 3
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
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- Baker NL, Morgelin M, Pace RA, Peat RA, Adams NE, Gardner RJ, Rowland LP, Miller G, De Jonghe P, Ceulemans B, Hannibal MC, Edwards M, Thompson EM, Jacobson R, Quinlivan RC, Aftimos S, Kornberg AJ, North KN, Bateman JF, Lamande SR. Molecular consequences of dominant Bethlem myopathy collagen VI mutations. Ann Neurol. 2007 Oct;62(4):390-405. doi: 10.1002/ana.21213. Citation on PubMed
- Baker NL, Morgelin M, Peat R, Goemans N, North KN, Bateman JF, Lamande SR. Dominant collagen VI mutations are a common cause of Ullrich congenital muscular dystrophy. Hum Mol Genet. 2005 Jan 15;14(2):279-93. doi: 10.1093/hmg/ddi025. Epub 2004 Nov 24. Citation on PubMed
- Bonnemann CG. The collagen VI-related myopathies: muscle meets its matrix. Nat Rev Neurol. 2011 Jun 21;7(7):379-90. doi: 10.1038/nrneurol.2011.81. Citation on PubMed
- Bushby KM, Collins J, Hicks D. Collagen type VI myopathies. Adv Exp Med Biol. 2014;802:185-99. doi: 10.1007/978-94-007-7893-1_12. Citation on PubMed
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