SEARCH RESULTS FOR: Osteogenesis-Imperfecta

Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI): Pathogenesis and clinical findings Autosomal dominant (or less commonly autosomal recessive or de novo) mutation in COL1A1 or COL1A2 genes (collagen, type I, alpha 1 or 2) Loss of function of one copy of COL1A1 (collagen, type 1, alpha 1) OI Type I (mildest form) Osteogenesis Imperfecta Group of genetic disorders in which mutations impair the production or structure of type I collagen ↓ Synthesis of structurally normal type I collagen Mildly short stature ↓ Collagen in sclera of eyes Thin & translucent sclera Blue-colored choroid layer underneath the sclera is more visible ↑ Risk of scleral rupture Blue sclerae ↑ Bone fragility Fractures in infancy & adulthood Ossicles are brittle & misshapen Cubitus varus (elbow bends in towards body) Conductive hearing impairment Legend: Abnormal dentin (layer underneath enamel) development Dentinogenesis imperfecta (opalescent teeth) ↑ Tooth fractures & dental caries Extremely fragile & weak bones & connective tissue Progressive fracturing of ribs & underdevelopment of thoracic cavity (pectus deformities) Bowing &/or angulation deformities of long bones in- utero Heterozygous glycine substitution mutation in COL1A1 or COL1A2 OI Type II Synthesis of abnormal quality & ↓ quantity of type I collagen Improper bone mineralization Minimal calvarial (bones of skull) mineralization Multiple prenatal fractures Translucent skull on prenatal ultrasound Degeneration of cochlear structures Sensorineural hearing impairment Restricted lung growth Inadequate alveolar development & impaired gas exchange Severe respiratory insufficiency Beaded appearance of ribs on prenatal imaging Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Perinatal death or death by 4 weeks of age (90%) Authors: Berna Ilchi Reviewers: Annie Pham Emily J. Doucette Taylor Krawec Danielle Nelson* * MD at time of publication Published Aug 16 2025 on www.thecalgaryguide.com