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collagen

collagen disorders

collagen

  • collagen refers to a group of proteins which are the main component of connective tissue and the most abundant protein in mammals making up 25-35% of total body protein.
  • 90% of total body collagen is of type I but there are at least 28 types of collagen, the most common are:
    • collagen I: skin, tendon, vascular ligature, organs, bone
    • collagen II: hyaline cartilage, vitreous humour of eye
    • collagen III: reticular fibres, commonly found with type I
    • collagen IV: cell basement membrane
    • collagen V: cell surfaces, hair, placenta
  • it is mainly produced by fibroblasts
  • it is a triple helix generally composed of two identical chains (α1) and an addition chain (α2)
  • vitamin C is essential for the production of collagen and deficient states result in scurvy
  • female sex hormones such as progesterone and relaxin alter collagen structure - important in allowing the pelvic girdle to expand in labour, but which may also contribute to joint hypermobility problems
  • collagen is broken down for tissue remodelling by collagenase
  • aging results in increased cross-linked collagen
  • gelatin is collagen that has been irreversibly hydrolysed

collagen vascular disorders

genetic defects

  • see also wikipedia
  • NB. Marfan's syndrome is caused by genetic defect of FBN1, the gene responsible for production of the connective tissue protein, fibrillin-1

collagen I (COL1A1, COL1A2 genes)

collagen II (COL2A1 gene)

  • collagenopathy, types II and XI
    • Stickler syndrome - AD trait; distinctive facial abnormalities (incl. Pierre Robin sequence), ocular problems (near-sightedness, cataracts), hearing loss, and joint problems
  • Achondrogenesis type 2
  • spondyloperipheral dysplasia
  • Spondyloepiphyseal dysplasia congenita
  • early onset familial primary osteoarthritis

collagen III (COL3A1 genes)

  • Ehlers-Danlos syndrome
  • Dupuytren's contracture

collagen IV (COL4A1, COL4A2, COL4A3, COL4A4, COL4A5, COL4A6 genes)

collagen V (COL5A1, COL5A2, COL5A3 genes)

  • Ehlers-Danlos syndrome (classical)

collagen VI (COL6A1, COL6A2, COL6A3, COL6A5 genes)

  • Ulrich myopathy
  • Bethlem myopathy
  • atopic dermatitis

collagen VII (COL7A1 gene)

  • epidermolysis bullosa dystrophica

collagen VIII (COL8A1, COL8A2 genes)

  • posterior polymorphous corneal dystrophy 2

collagen IX (COL9A1, COL9A2, and COL9A3 genes)

collagen.txt · Last modified: 2013/02/04 18:26 (external edit)