collagen

Definition : Collagen is the most common protein in the animal world, providing the extracellular framework for all multicellular organisms.

The collagens are composed of a triple helix of three polypeptide α chains, having a gly-x-y repeating sequence. Currently 27 different types of collagens encoded by 41 genes ( COLs ) dispersed on at least 14 chromosomes are known.

Pathology

 anomalies of collagen / abnormal collagen

• mutations of COLs genes
  • osteogenesis imperfecta

 collagen hyalinization
 collagen necrobiosis