autosomal dominant osteopetrosis

Autosomal dominant osteopetrosis is the less severe type of osteopetrosis and should be considered and compared with the other subtype autosomal recessive osteopetrosis. The autosomal dominant (AD) type is less severe than its autosomal recessive (AR) mate. Hence, it is also given the name "benign" or "adult" since patients survive into adulthood (something that is unlikely with the AR-type).

Clinical presentation

  • multiple fractures
  • multiple cranial nerve compression: e.g. leading to deafness and/or blindness
  • hepatosplenomegaly: from extramedullary hematopoiesis due to bone red marrow replacement 

Pathology

In all osteopetrosis (whether AD or AR) there is a deficiency of osteoclast function and the result is that bone becomes dense. However, their altered internal architecture renders them weak. Therefore, patients have dense, sclerotic, fragile bones that fracture easily.

Classification
  • type I: pronounced osteosclerosis of cranial vault with clinical presentation as cranial nerve palsies
  • type II: end plate thickening of vertebrae (sandwich vertebra) and endobones ("bone-within-bone" appearance) in the pelvis, increased risk of fracture

Radiographic features

Treatment and prognosis

Treatment is with bone marrow transplant and resultant normalization of bone production. Prognosis for the AD adult subtype is good with a reasonable life expectancy.

Differential diagnosis 

General imaging differential considerations include:

See also

Siehe auch:
und weiter: