Osteogenesis imperfecta (more commonly known as brittle bone disease) is a group of disorders of collagen metabolism resulting in bone fragility and fractures. The most common, and milder, form of osteogenesis imperfecta is type 1

Subtype of osteogenesis imperfecta

• Type I - The collagen is normal quality but insufficient quantity.
• Type II - Poor collagen quantity and quality.
• Type III - Collagen poorly formed. Normal quantity.
• Type IV - Sufficient collagen quantity but poor quality.

Pathophysiology

• Autosomal dominant
• Defective osteoid formation due to congenital inability to produce adequate intercellular substances like osteoid, collagen and dentine.
• Failure of maturation of collagen in all the connective tissues.

PC

• presents in childhood
• fractures following minor trauma
• blue sclera
• deafness secondary to otosclerosis
• dental imperfections are common
• Scoliosis due to weak spinal bones