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  • Brittle bone disease


  • 756.51 Osteogenesis imperfecta


  • Q78.0 Osteogenesis imperfecta


  • 5B: Impaired Neuromotor Development


A 5-year-old is referred to physical therapy following removal of a cast for a femur fracture and subsequent diagnosis of osteogenesis imperfecta (OI). The child has decreased active and passive knee range of motion (ROM). The child presents with a leg-length difference and decreased strength in the hip, knee, and ankle on the involved side.



  • Autosomal dominant genetic disorder that affects Type I collagen resulting in osteopenia and frequent fractures that may be apparent in a newborn infant

Essentials of Diagnosis

  • Four types

    • Type I: Mild (most common)

    • Type II: Perinatal lethal

    • Type III: Progressive deforming

    • Type IV: Deforming with normal scleras

  • Types I and IV do not have fractures while in utero

  • Type II characterized by fractures in utero

  • Type III characterized by fractures at birth or as infant

General Considerations

  • Disorder results from Type I collagen impairment that affects skin, bone, connective tissue of organs (including GI tract), and vascular system

  • Type I: Fewer fractures after puberty; short stature and hearing loss as adult; blue sclera

  • Type II: Usually results in death during infancy due to respiratory problems

  • Type III: Usually nonambulatory as an adult due to progressive deformities from multiple fractures over time; sclera affected; short stature, scoliosis

  • Type IV: Short stature as adult, fractures continue as adult, but remains ambulatory; scoliosis; hearing loss; sclera unaffected

FIGURE 247-1

Osteogenesis imperfecta (OI) Blue sclerae are the most characteristic mucocutaneous feature of patients with mild OI. (From Goldsmith LA, Katz S, Gilchrest B, Paller A, Leffell D, Wolff K, eds. Fitzpatrick’s Dermatology in General Medicine. 8th ed. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)


  • 1 in 20,000 births1

  • Infants

  • Males and females affected equally1

FIGURE 247-2

Gonadal mosaicism for type II osteogenesis imperfecta (OI). In this idealized pedigree, the phenotypically normal father (indicated with the arrow) has had two children by different mates, each of whom is affected with autosomal dominant type II OI. Analysis of the father showed that some of his spermatozoa carried a COL1A1 mutation, indicating that the explanation for this unusual pedigree is germline mosaicism. (Redrawn from Cohn DH, Starman BJ, Blumberg B, Byers PH,. Recurrence of lethal osteogenesis imperfecta due to parental mosaicism for a dominant mutation in a human type I collagengene [COL1A1]. Am J Hum Genet. 1990;46:591–601.)

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