Normal Function
The COL6A1 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 COL6A1 gene is the alpha(α)1(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 COL6A1 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 α1(VI) chain. The most frequently affected amino acid is glycine; changes to this building block disrupt the structure of the α1(VI) chain. Other variants can also disrupt the structure of the α1(VI) chain.
Variants in the COL6A1 gene affect type VI collagen in different ways. Some variants lead to altered α1(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 α1(VI) chain, which impedes formation of type VI collagen. All of these COL6A1 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 α1(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.
Limb-girdle muscular dystrophy
MedlinePlus Genetics provides information about Limb-girdle muscular dystrophy
Other Names for This Gene
- alpha 1 (VI) chain (61 AA)
- CO6A1_HUMAN
- collagen alpha-1(VI) chain
- collagen type VI alpha 1
- collagen VI, alpha-1 polypeptide
- collagen, type VI, alpha 1
Genomic Location
The
COL6A1 gene is found on chromosome 21.