Osteogenesis Imperfecta
- Several variants
- best is type 1 and also the most common
- worst is type 2
- worse to best: 2341
- blue sclera only in types 1,2
- wormian bones: wormy, irregular lucencies
- subtype a: no dentinogenesis imperfecta (which causes a bluish,
opalescent sheen on teeth due to defective dentin
Type 1
- Autosomal dominant; quantitative defect in Type I procollagen
- commonest and mildest form of OI
- bone fragility is mild to moderate; healing occurs without deformity
- blue sclera,
early hearing loss, easy bruising, short stature
- XR shows osteoperosis, wormian bones of skull
- type Ia, no dentinogenesis imperfecta
- type Ib: dentinogenesis imperfecta
Type II
- autosomal dominant or recessive
- lethal perinatal; extreme fragility, in-utero
fractures; IUGR
- soft, large cranium
- XR: beading of the ribs is characteristic (indicating multiple fx); broad
and crumpled femorae, as well as long bones; hypoplastic pelvis with
flattening of the acetabular roofs and iliac crests
- blue sclera
Type III
- autosomal recessive
- severe bone fragility; extreme short stature
- WHITE SCLERA
Type IV
- autosomal dominant
- WHITE SCLERA
- joint hyperextensibility, bowing of bones, moderate short stature
- Type IVa: no dentinogenesis imperfecta
- type IVb: dentinogenesis imperfecta
CHLA board review course 2005
Baraitser and Winter, 1996. Color Atlas of Congenital Malformation Syndromes