This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
Osteogenesis imperfect is due to a defect in: 
Select and explain. 
A. Collagen 1, B. Collagen 2, C. Collagen 3, D. Collagen 4
A: Collagen 1
Answer: A: Collagen 1 
Explanation: (Refer: Robbins Pathologic Basis of Disease, 8thedition, pg no: 1211-1213)
Major Types of Collagen in Body