IS case 466: Osteogenesis imperfecta, type II

Mary Fontanella, MD

University of Rochester


Imaging Sciences URMC 2010
Publication Date: 2010-08-30

History

Patient is a newborn, 37-week gestation, infant with skeletal abnormalities on prenatal ultrasound.

Findings

Babygram obtained shortly after birth demonstrated numerous bilateral rib fractures in various stages of healing and bell-shaped chest, two fractures of the left humerus, one proximal and one distal, fractures of the right radius and ulna shaft, healing fractures of both femurs, fracture of the right tibia and fibula and bowed left tibia and fibula consistent with old healed fracture.

Diagnosis

Osteogenesis imperfecta, type II

Discussion

Osteogenesis imperfecta (OI) is a disorder of type I collagen synthesis that results in bone fragility with fractures and easy deformability. There are four distinct types.

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Type I is the most common form of OI and is associated with the best prognosis. The mode of inheritance is autosomal dominant. The distinguishing clinical features of type I are blue sclerae and conductive hearing loss. Bone fragility is mild, and there are minimal bony deformities. The stature of patients with type I OI is often normal or near normal. Ligamentous hyperlaxity is common. Approximately 20% of patients have kyphoscoliosis. Inheritance is autosomal dominant. *

Type II is the most severe form and is characterized by extreme bone fragility that leads to intrauterine or early infant death, most often due to respiratory failure. The sclerae are blue and occasionally dark blue or black. Features include intrauterine growth retardation, thin and beaded ribs, crumpled long bones, and limited cranial and/or facial bone ossification. Limbs are short, curved, and angulated. Inheritance is autosomal recessive. *

Type III is the next most severe form of OI after type II and is the most severe form in which survival extends beyond the perinatal period. It is marked by severe bone fragility and osteopenia, which is progressively deforming and affects the long bones, skull and spine; fractures are often present at birth and there is severe postnatal growth failure. Inheritance is autosomal recessive. *

Type IV OI is distinguished from type I OI by the slightly increased, though still variable, severity of bone fragility and by the presence of normal sclerae. There is mild to moderate deformity of the long bones and spine with variable incidence of fracture. Basilar impression of the skull, with consequent brainstem compression, is reported in 70% of patients. Compared with type I OI, hearing loss is less common in type IV.

In forms where patients survive into childhood, the presence of wormian bones can be helpful in distinguishing multiple fractures secondary to OI from cases of child abuse.

References

  1. Shoenfeld Y. Osteogenesis imperfecta. Review of the literature with presentation of 29 cases. Am J Dis Child. 1975 Jun;129(6):679-87. PMID: 1098447
  2. Ablin DS, Greenspan A, Reinhart M, Grix A. Differentiation of child abuse from osteogenesis imperfecta. AJR Am J Roentgenol. 1990 May;154(5):1035-46. PMID: 2108539

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