Osteogenesis Imperfecta

Question 1

What is abnormal in osteogenesis imperfecta?

Answer 1

Qualitative defect in Type I collagen synthesis; physeal osteoblasts cannot form sufficient osteoid and periosteal osteoblasts cannot form sufficient osteoid and therefore cannot remodel normally

Question 2

What is the genetic mutation in osteogenesis imperfecta”

Answer 2

COL1A1 and COL1A2; causes abnormal collagen cross-linking via a glycine substitution in the procollagen molecule

Question 3

Which form of osteogenesis imperfecta is the worst?

Answer 3

Type II is lethal in perinatal period; Type III has multiple fractures at birth and is the most severe survivable form

Question 4

What is the most common cause of myelopathy in osteogenesis imperfecta patients?

Answer 4

Basilar invagination

Question 5

Which pediatric congenital disorders is caused by a glycine substitution in the procollagen molecule?

Answer 5

Osteogenesis imperfecta

Question 6

What causes the zebra lines on xray in patients being treated for osteogenesis imperfecta?

Answer 6

Bisphosphonates

Question 7

What are the surgical options for long bone fractures in patients with osteogenesis imperfecta?

Answer 7

Less than 2yo: observation
> 2yo: consider surgical options below
Severe deformity: Sofield-Miller procedure (“bone kabob”)
Non-telescoping rods: Rush Rods, Williams Rods
Telescoping rods: Fassier-Duval, Sheffield Rod, Bailey-Dubow Rod

Question 8

When is surgery indicated for scoliosis in patients with osteogenesis imperfecta?

Answer 8

Mild OI: curve >45°

Severe OI: curve >35°