Collagen VI acts as a cell-binding protein. Trimers composed of three different chains: alpha-1(VI), alpha-2(VI), and alpha-3(VI) or alpha-5(VI) or alpha-6(VI). Prolines at the third position of the tripeptide repeating unit (G-X-Y) are hydroxylated in some or all of the chains. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. A mutation in COL6A1 is the cause of autosomal recessive limb-girdle muscular dystrophy. The affected individual with a homozygous recessive COL6A1 mutation showed progressive muscle weakness with an onset at the age of 4 years and loss of ambulation at the age of 15 years. Muscle biopsy showed end stage dystrophy. Belongs to the type VI collagen family.