Disorders of Collagen Synthesis

Question 1

Scurvy

Answer 1

hydroxylation step

hydroxylases

Question 2

Osteogenesis imperfecta

Answer 2

formation of triple helix

Question 3

Copper deficiency (Menkes disease)

Answer 3

cross linking step

lysyl oxidase

Question 4

Genetic bone disorder (brittle bone disease) caused by variety of gene defects - COL1A1 and COL1A2

Answer 4

Osteogenesis Imperfecta

AD
type I collagen

Question 5

Manifestations of Osteogenesis Imperfecta

Answer 5

Multiple fractures and bone deformities after minimal trauma

Blue Sclerae d.t. translucent CR over choroidal veins

Tooth abnormalities - opalescent teeth (wear easily d.t. lack of dentin) - dentinogenesis imperfecta

Conductive hearing loss (abnormal ossicles)

Question 6

Faulty collagen synthesis causing hyperextensible, hypermobile joints, and tendency to bleed (easy bruising)

Answer 6

Ehlers Danlos Syndrome

Hypermobility type - MC

Classical type (joint and skin) - TYPE V

Vascular type - TYPE III

Question 7

X linked recessive CT disease caused by impaired copper absorption and transport d.t. defective Menkes protein (ATP7A)

Answer 7

Menkes disease

low copper levels – decreased activity of lysyl oxidase