The collagens are a superfamily of proteins that play a role in maintaining the integrity of various tissues. Collagens are extracellular matrix proteins and have a triple helical domain as their common structural element. Collagen VI is a major structural component of microfibrils. The basic structural unit of collagen VI is a heterotrimer of the alpha 1(VI), alpha 2(VI), and alpha 3(VI) chains. Mutations in the genes that code for the collagen VI subunits result in the autosomal dominant disorder, Bethlem myopathy.
