CASE 6456 Published on 27.03.2008

Osteogenesis imperfecta

Section

Paediatric radiology

Case Type

Clinical Cases

Authors

Dr Anwen Jelbert, Dr Demosthenis Michaelides

Patient

9 months, male

Clinical History
We present a case of osteogenesis imperfecta in a nine month old child and demonstrate the major radiographic features.
Imaging Findings
A 9 month old child had previously been demonstrated to have multiple fractures in utero. A skeletal survey was performed to assess the current state of the multiple bony deformities.
Discussion
Osteogenesis imperfecta (OI) is a constellation of congenital disorders due to a deficiency or defect in type 1 collagen, resulting in increased bone fragility. It is divided into four sub-groups, depending on the defect or deficiency present and their varied clinical features, but the overall hallmark is of osteoporosis.   Type 1 is traditionally known as the “tarda” form, although the degree of fragility varies from mild to severe. It is due to an insufficient quantity of normal quality collagen. A few will have fractures at birth, but generally it presents between the ages of 2 and 6. Bones are gracile with fracture-induced deformity and healing with exuberant callus. Multiple growth arrest lines will be seen in all types following repeated fractures. Wormian bones may be present and may disappear in adulthood. They may also have blue sclera and otosclerosis. Abnormal dentinogenesis may or may not be present. It is transmitted via autosomal dominant inheritance.   Type 2, previously known as “OI congenita”, is the lethal perinatal form with severe osseous fragility, due to deficient quantity and quality of collagen. It is divided into three subtypes. They all have degrees of skull osteopenia, rib and long bone deformity and blue sclera. Type A (autosomal dominant inheritance) demonstrates platyspondyly. In type B (autosomal recessive inheritance) vertebral body and disc height are similar. Type C (autosomal dominant or recessive inheritance) demonstrates normal vertebral body height. Some may be due to new genetic mutations. Perinatal death occurs secondary to multiple fractures and intracranial bleeding, respiratory insufficiency or cervical cord compression due to skull base deformity.   Type 3 is rare. There is a normal quantity of insufficient quality collagen. It is clinically similar to type 2, but with a longer survival. There is moderate to severe osseous fragility resulting in severe deformity and dwarfing. Birth fractures are present in 2/3 of cases. Wormian bones are present, but the sclera are a pale blue, becoming paler with time. There may be bubbly cystic expansion of the metaphyses of long bones known as popcorn calcification. Inheritance may be autosomal recessive or a new dominant mutation.   Type 4 is also rare, and again due to a normal quantity of poor quality collagen. It is generally mild in severity with mild to moderate bowing and deformity of long bones, which are of normal length. It may be divided into types A (absence) and type B (presence) of dentogenesis imperfecta. There is early onset of deafness, but sclera are normal.      
Differential Diagnosis List
Osteogenesis imperfecta type 3.
Final Diagnosis
Osteogenesis imperfecta type 3.
Case information
URL: https://www.eurorad.org/case/6456
DOI: 10.1594/EURORAD/CASE.6456
ISSN: 1563-4086

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