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 and is more elastic than 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

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

see wikipedia
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 is more elastic than collagen I
people with joint hypermobility disorders and syndromes have a higher ratio of collagen III to collagen I (28-46% cw normal of 18-21%)
Ehlers-Danlos syndrome
Dupuytren's contracture