Definition
Osteogenesis imperfecta is a heritable disorder of connective tissue characterised by bone fragility. The common classical forms result from abnormalities of type I collagen, most often involving COL1A1 or COL1A2.
Clinical features
- recurrent low-energy fractures
- long-bone deformity
- short stature in more severe disease
- scoliosis
- blue sclerae in some types
- dentinogenesis imperfecta
- hearing impairment
- ligamentous laxity
Sillence classification
Type I
- Mildest common form
- Blue sclerae are typical
- Fractures occur but deformity is limited
Type II
- Perinatal lethal form
- Severe skeletal fragility and deformity
Type III
- Severe progressive deforming form
- Multiple fractures and marked short stature
Type IV
- Intermediate severity
- Sclerae are often normal
Several additional molecular types are now recognised, but the Sillence groups remain clinically useful.
Radiographic features
- osteopenia
- multiple fractures of different ages
- bowing deformities
- thin cortices
- vertebral compression
- wormian bones may be seen in the skull
Management
Management is multidisciplinary.
- fracture prevention and safe mobilisation
- physiotherapy and rehabilitation
- bisphosphonates in selected children
- fracture treatment with attention to fragile bone
- realignment osteotomy and intramedullary rodding for progressive long-bone deformity
- surveillance for scoliosis, hearing and dental problems
References
- Orthobullets. Osteogenesis Imperfecta.