OSTEOGENESIS IMPERFECTA

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

a. Scurvy

b. Osteogenesis imperfecta

c. Ochronosis

d. Fibrous dysplasia

 

OSTEOGENESIS IMPERFECTA

Synonyms =

• Ø fragilitas ossium
• Ø Osteopsathyrosis
• Ø Lobstein’s disease
• Ø Vrolik’s disease
• Ø Brittle bone disease

 

The disease is mainly due to defect in type 1 Collagen due to glycine substitution in the pro collagen molecule

 

Triad of OI =

• Ø Blue Sclerae
• Ø Dentinogenesis imperfect
• Ø Generalized osteoporosis

 

Classification = ( Shapiro et al )

• Ø Congenita A ( fractures in utero / birth with 100% mortality )
• Ø Congenita B ( fractures in utero / birth with 8% mortality )
• Ø Tarda A ( fractures before walking age )
• Ø Tarda B ( fractures after walking age )

 

Extra skeletal tissues and organs affected by type 1 collagen defects

• Ø Sclera
• Ø Dentin
• Ø Bone
• Ø Ear
• Ø Skin
• Ø Heart valves
• Ø Vessels
• Ø Capillaries

 

The most common cause of spontaneous multiple fractures all over the body ,  without any history of trauma , in different stages of healing , mainly involving the long bones , is Osteogenesis Imperfecta provided there are no superficial marks of any violence e.g abrasion , laceration , incised wound etc. , else the most common cause becomes Battered baby syndrome / Caffey ‘s syndrome.