Collagen

Question 1

Osteogenesis Imperfecta (OI)

Answer 1

Type I OI: collagen malfunction (2 functions: connective tissue, and bone composition). Glycine (part of Collagen triple helix) mutation common
fragile bones, fractures, triangular face, cyanotic (blue) sclera, hearing loss, scoliosis, brittle teeth.

Type II OI: lethal, death during embryogenesis or birth

Bisphosphonates: increase osteoclast apoptosis. decrease osteoblast apop

Question 2

Scurvy

Answer 2

Ascorbate (Vitamin C) deficiency. Vit C is cofactor for Hydroxylation of Proline to Hydroxyproline (stabilizes Collagen Triple Helix).
malnourishment (asi alcoholics). spongy bleeding gums, anemia, poor wound healing, follicular hyperkeratosis, corkscrew hairs

Question 3

Menkes’

Answer 3

Cu+ (copper) def or Lysyl oxidase def: no collagen cross-linking. kinky, steel colored hairs, growth retardation, neural issues d/t copper deficiency

Question 4

Ehlers-Danlos

Answer 4

ECM Procollagen Peptidase def. Procollagen not cleaved to tropocollagen (collagen). No fibrils. loose joints

Question 5

Alport’s

Answer 5

Type IV (6) collagen (basement membranes) mutation. kidney, ear, eye malfunction. 
proteinuria, hypertension, ESRD (end stage renal disease) hearing loss,

Question 6

Marfan’s

Answer 6

fibrillin mutation. fibrillin provides scaffold for elastin.
long, slender limbs dislocated lenses, aortic root dilation. serious complication: aortic aneurysm, aortic dissection.
appear similar to homocystinuria patients, but homocystinuria–>mental retardation. Marfan’s–>normal IQ