Osteogenesis Imperfecta

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Osteogenesis Imperfecta

• Dr. Marvin Miller
• The Childrens Medical Center
• Dayton, Ohio

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Osteogenesis Imperfecta
-Genetic disorder of collagen -Can present with
fractures as a result of minimal physical forces
applied to the fractured bone(s) -Traditionally
diagnosed by collagen test on skin biopsy 15
false negative rate
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Genetics of OI

• OI is caused by mutations in the COL1A1 or COL1A2
  genes which encode the alpha1 and alpha 2 chains
  of type 1 collagen respectively

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CLASSIFICATION OF OI
OI TYPE 1 BONE FRAGILITY MILD/MOD SCLERAE BLUE COMMENTS COMMON
2 MOST SEVERE BLUE LETHAL
3 SEVERE WHITE SKELETAL DEFORMATIES
4 VARIABLE WHITE UNCOMMON
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OI-TYPE 1

• BLUE SCLERAE
• WORMIAN BONES
• SHORT STATURE
• HEARING LOSS50
• DENTINOGENESIS IMPERFECTA30
• FREQUENCY120,000

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Dentinogenesis Imperfecta
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Wormian Bones
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Genetics of OI
Sporadic (25) Familial
(75)
OI
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Diagnosis of Osteogenesis Imperfecta
-Collagen test -DNA test -Bone density test
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Confirmatory Testing for OI

• Collagen Test
• skin biopsy
• costs 900
• 3 weeks for results
• 15 false negative rate
• DNA Test
• Blood
• costs 1,800
• 4-5 weeks for results

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Treatment of OI Fractures
Acute management of fractures Prevention of
fractures -Lifestyle-minimal contact
sports -Increase bone loading-exercise -Drugs-bi
sphosphonates
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Pamidronate to Treat Severe OI
30 children, ages 3-16 years, with severe OI
treated with intravenous pamidronate Pamidronate
given q 4-6 months over 1.3 - 5 years Evidence
of improvement -DEXA increased bone
density -Decreased frequency of
fractures -Relief of chronic pain and fatigue
Glorieux et al, NEJM 339947-952, 1998