Types of collagen, synthesis, and diseases

Question 1

Granulation tissue

Answer 1

III

Question 2

OI results from impairement of:

Answer 2

Alpha triple helix formation during collagen synthesis

Question 3

Skin

Answer 3

Mainly I, some III

Question 3

What cofactor is required for hydroxylation of proline and lysine during collagen synthesis?

Answer 3

Vitamin C

Question 3

In what form is collagen exocytosed into ECM during synthesis?

Answer 3

Procollagen (already in triple helix)

Question 3

Most common type of Ehlers-Danlos?

Answer 3

Hypermobile type (joint instability)

Question 4

Where is the alpha chain triple helix of precollagen formed?

Answer 4

RER of fibroblast

Question 5

Cornea

Answer 5

I

Question 6

Consensus sequence of collage

Answer 6

Gly-X-Y

Question 6

Best reflection of collagen synthesis?

Answer 6

Glycine uptake by fibroblasts

Question 7

Where is type IV collagen found?

Answer 7

Basement membrane, basal lamina, lens

Question 7

What causes Menke disease?

Answer 7

Lack of copper transport and absorption –> no copper for lysyl oxidase cross-linking of lysine-hydroxylysine

Question 8

Fascia

Answer 8

I

Question 9

Where is type I collagen found?

Answer 9

Bone, skin, tendon, fascia, dentin, cornea, late wound repair

Question 10

Kinky hair + growth retardation + hypotonia

Answer 10

Menke disease

Question 11

Lens

Answer 11

IV

Question 11

Which preprocollagen residues are hydroxylated in the RER of fibroblasts?

Answer 11

Proline and lysine

Question 12

Uterus

Answer 12

III

Question 13

Where is type III collagen found?

Answer 13

Blood vessels, granulation tissue, fetal tissue, uterus, skin

Question 13

Hyperextensible skin + easy bruising/tendency to bleed + hypermobile joints

Answer 13

Ehlers-Danos

Question 14

Basement membrane

Answer 14

IV

Question 15

Multiple fractures + hearing loss + dental imperfections

Answer 15

OI

Question 17

Tendon

Answer 17

I

Question 19

Where is type II collagen found?

Answer 19

Cartilage (including hyaline), nucleus pulposus, vitreous body

Question 19

Basal lamina

Answer 19

IV

Question 21

Nucleus pulposus

Answer 21

II

Question 22

Is type I collagen defective in OI?

Answer 22

No, just reduced production of otherwise normal type I collagen

Question 23

Which residue of preprocollagen gets glycosylated in the RER of fibroblasts?

Answer 23

Hydroxylysine

Question 24

Scurvy results in failure of which step of collagen synthesis?

Answer 24

Hydroxylation of proline and lysine in RER of fibroblast

Question 26

Which type of collagen is underproduced in osteogensis imperfecta?

Answer 26

I

Question 27

Name 5 diseases associated with collagen.

Answer 27

1. OI (no type I)
2. Ehlers-Danlos (no cross-linking)
3. Alport (defective IV)
4. Goodpasture’s (autoantibodies against IV)
5. Menkes disease (no copper for lysyl oxidase)

Question 29

Bone

Answer 29

I

Question 30

Cartilage

Answer 30

II

Question 32

Late wound repair

Answer 32

I

Question 33

Risk of joint dislocation, aortic or berry aneurysms, organ rupture

Answer 33

Ehlers-Danlos

Question 35

Blood vessels

Answer 35

III

Question 36

Most common type of collagen

Answer 36

I

Question 37

Which steps in collagen synthesis occur outside the fibroblast?

Answer 37

Cleave of terminal disulfide-bonds of procollagen to form tropocollagen

Cross-linking of lysine-hydroxylysine

Question 38

Dentin

Answer 38

I

Question 40

Which enzyme cross-links collagen? What is its co-factor?

Answer 40

Lysyl oxidase

Copper

Question 41

Mode of inheritance: OI

Answer 41

AD

Question 42

Fetal tissue

Answer 42

III

Question 43

Vitreous body

Answer 43

II