Some Viva Questions From Osteogenesis Imperfecta: Bone Diseases

Q. What is osteopenia? How it occurs in case of OI?

- Mutation of gene coding for type I collagen > defect of type I collagen biosynthesis (in organic matrix) > failure of foetal collagen to be transformed into mature collagen > tendency for fracture and defective bone healing called osteopenia.

Q. Why OI shows blue sclera?
- Sclera of eye become very thin due to defective type I collagen formation. Hence the pigmented choroid shows through and produces bluish colour.

Q. Why there is hearing loss in OI?
- Due to compressions of cranial nerves or their branches

Q. What are Wormian bones?
- Wormian bones are multiple sutural bones found in the skull which fail to fuse.

Q. Name of other diseases in which blue sclera can be seen.
- 1. Osteopetrosis
  2. Paget's disease
  3. Foetal Rickets
  4. Turner syndrome
  5. Marfan syndrome
  6. Ehlers-Danlos syndrome
  7. Normal infants