Clinical Fiber Disorders

Question 1

Ehlers-Danlos Type IV

Answer 1

Mutation in type III collagen fibers (reticular fibers)

Varicose veins, aortic rupture, intestinal rupture

Question 2

Ehlers-Danlos Type VI

Answer 2

Defective hydroxylation of lysine = destabilized collagen

Hyperelastic skin, rupture of eyeball

Question 3

Ehlers-Danlos Type VII

Answer 3

Mutation in type I collagen

Joint dislocation and hypermobility

Question 4

Scurvy

Answer 4

Decreased hydroxylation of proline secondary to vit. C deficiency. Tropocollagen molecules can’t aggregate

Gum ulceration and hemorrhages

Question 5

Osteogenesis Imperfecta

Answer 5

Mutation leads to reduced type I collagen synthesis

Spontaneous fractures and cardiac insufficiency

Question 6

Strickler Syndrome

Answer 6

Mutation in type II collagen

Myopia, hypoplasia of mandible, arthritis

Question 7

Marfan Syndrome

Answer 7

Mutation of fibrillin 1 gene

Aortic aneurysm/rupture, myopia, detached lens, skeletal defects (long thin arms/legs/toes/fingers, pectus excavatum, scoliosis)