Osteogenesis imperfecta
Osteogenesis imperfecta is the most common heritable connective tissue disorder, caused chiefly by autosomal dominant type I collagen gene defects that produce fragile, osteopenic bone with recurrent fractures, blue sclerae, and hearing loss, managed with bisphosphonates, fracture care, and multidisciplinary rehabilitation.
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What this article covers
- Overview
The most common heritable disorder of connective tissue, affecting an estimated 1 in 20,000 births, with autosomal dominant and recessive variants.
- Epidemiology
Prevalence approximately 1 in 20,000 births, making it the most common heritable connective tissue disorder.
- Risk factors
Family history of osteogenesis imperfecta (OI) or unexplained childhood fractures, reflecting the autosomal dominant inheritance of most cases.
- Pathophysiology
Mutation in COL1A1 or COL1A2 impairs formation of the type I collagen triple helix, the structural backbone of bone matrix, tendon, sclera, and dentin.
- Clinical features
Multiple fractures after minimal trauma, the hallmark feature, sometimes occurring during birth itself; long-bone deformity accumulates with repeated fracture and healing.
- Differential diagnosis
Child abuse (nonaccidental trauma): fractures of varying ages, posterior rib and metaphyseal "bucket handle" fractures, and injury inconsistent with the reported mechanism, without the blue sclerae…
- Diagnosis
OI is diagnosed clinically from a history of recurrent low-trauma fracture combined with characteristic extraskeletal features (blue sclerae, dentinogenesis imperfecta, hearing loss) and a positive…
- Management
First, treat each acute fracture with standard orthopedic care (splinting, casting, or surgical fixation as the fracture pattern requires), using padding and technique adapted to fragile bone to avoid iatrogenic injury.
- Complications
Recurrent fracture and cumulative skeletal deformity, the dominant source of lifelong morbidity.
- Prognosis
Mild (type 1) disease carries a normal or near-normal lifespan, with fracture frequency decreasing after puberty and good functional outcomes with therapy.
- Prevention
No primary prevention exists for a genetic disorder present from conception; the actionable target is preventing fracture and secondary complications in a patient already diagnosed.
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