Collagen D/O's

Question 1

collagen synthesis

• what aa most prevalent
• what cells does it happen in

Answer 1

• glycine (third of aa’s are glycine)

- synthesis in RER of fibroblasts

Question 2

intracellular collagen modifications (2)

Answer 2

1. hydroxylation of proline and lysines
2. glycosylations of pro-alpha chain hydroxylysine residues –> this leads to secondary structure triple helix

now it’s pro-collagen

Question 3

extracellular collagen modifications (2)

Answer 3

1. proteolytic processing (cleavage of disulfide rich terminal regions of procollagen –> now insoluble tropocollagen
2. cross-linking of many tropocollagens by lysine-hydroxylysine linkages to make collagen fibrils

Question 4

Osteogenesis imperfecta

• inheritance
• what collagen
• s/s’s

Answer 4

• AD
• decreased production of collagen I
• brittle bone -> easy fractures
• blue sclera b/c no covering over choroidal veins
• hearing loss b/c abnormal ossicles
• dental imperfections b/c dentin def

Question 5

Ehlers danlos syndrome

• inheritance
• types
• collagen involved
• s/s’s

Answer 5

• many kinds; AR or AD
• classical type ( joint and skin syndrome) if mutation in collagen V
• vascular type (organ and vascular rupture) if mutation in collagen III
• berry aneruysms, organ rupture, hypermobility, joint instability

Question 6

Menkes disease

• cause
• enzyme involved
• s/s’s

Answer 6

• impaired copper absorption and transport
• impaired lysyl oxidase (Cu is a cofactor) function
• brittle, kinky hair; growth retardation;l hypotonia

Question 7

Collagen 1 where (8)

Answer 7

1. dermis
2. tendons
3. ligaments
4. bone
5. dentin
6. cornea
7. blood vessels
8. scar tissue

Question 8

collagen 1 a/w what disease

Answer 8

osteogenesis imperfecta

Question 9

collagen 2 where (3)

Answer 9

1. cartilage
2. vitreous humor
3. nucleus pulposus

Question 10

collagen 3 where (7)

Answer 10

1. Skin
2. granulation tissue
3. blood vessels
4. lymphatics
5. lungs
6. intestines
7. bone marrow

Question 11

collagen 3 disease

Answer 11

Ehlers-Danlos syndrome

Question 12

collagen 4 where

Answer 12

basement MB

Question 13

collagen 4 disease

Answer 13

Alport syndrome