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Definition / general | Radiology description | Gross description | Microscopic (histologic) descriptionCite this page: Pernick N Osteogenesis imperfecta. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/boneosteogenesisimperfecta.html. Accessed November 27th, 2024.
Definition / general
- Also called brittle bone disease
- One of the most common congenital connective tissue matrix diseases
- Disease of type I collagen due to mutations in genes coding for alpha 1 - 2 collagen chains, usually autosomal dominant
- A type of osteoporosis with marked cortical thinning and attenuation of trabeculae, plus other collagen related signs / symptoms
- Skeletal abnormalities may be mild (reduced amounts of normal collagen) or severe/lethal (abnormal polypeptide chains cannot form collagen triple helix); associated with short stature and increased fractures (hundreds of minor / major fractures during childhood, usually in lower limb, often involving growth plate fragmentation around knees)
- Blue sclera: due to translucent sclera and visualization of choroid
- Hearing loss: sensorineural defect and impeded conduction due to abnormalities of middle ear bones
- Dental imperfections: small, misshapen, blue - yellow teeth, due to dentin deficiency
- Type I: usually acquired mutation, autosomal dominant, normal lifespan with increased fractures during childhood but decreasing after puberty
- Type II: usually autosomal recessive, uniformly fatal due to extraordinary bone fragility with multiple intrauterine fractures; unstable triple helix
- Type III: autosomal dominant or recessive, growth retardation, but otherwise like type I
- Type IV: autosomal dominant, short stature, but otherwise like type I
Radiology description
- Nodules of cartilage at growth plate resembling a bag of popcorn
- Marked swelling of distal femur
Gross description
- Cartilaginous nodules due to fragmentation of growth plate
Microscopic (histologic) description
- Severe forms lack an organized trabecular pattern
- Crowded osteocytes within bone (due to reduced collagen synthesis)
- Large areas of woven bone
- Less severe forms still have crowded osteocytes with thin lamellar bone