Osteogenesis imperfecta
A genetic disorder characterized by impaired osteogenesis that results in skeletal deformities and brittle bones that fracture easily
Epidemiology
- Various genetic defects; most commonly autosomal dominant mutations in COL1A1 or COL1A2 genes
Etiology
Pathophysiology
↓ synthesis of normal type I collagen
Clinical features
Osteogenesis imperfecta type I (the mildest and most common form)
- Growth delay
- Skeletal deformities, brittle bones
- Bowing of bones and saber shins
- Fractures during childbirth and recurrently from minimal trauma thereafter
- Blue sclerae (choroidal veins show through the thin, translucent sclera)
- Progressive hearing loss due to deformation, fracture, and/or atrophy of the ossicles
- Brittle, opalescent teeth
Osteogenesis imperfecta type II
- Most severe form; usually fatal within the first year of life
- Multiple intrauterine and/or perinatal fractures
- Micromelia, hypoplastic thorax
- Underdeveloped lungs leading to respiratory problems