Autosomal dominant osteopetrosis
Updates to Article Attributes
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 haematopoiesis 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 become dense. However, their altered internal architecture renders them weak. Therefore, patients have dense, sclerotic, fragile bones that fracture easily.
Radiographic features
- bone within a bone appearance (case 1): one of the classical appearances of autosomal dominant osteopetrosis
- Erlenmeyer flask type deformity of the tubular bones
- Sandwich vertebrae: dense bands of sclerosis parallel to the endplates
- alternating radiolucent metaphyseal bands
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
Treatment and prognosis
Treatment is with bone marrow transplant and resultant normalisation of bone production. Prognosis for the AD adult subtype is good with a reasonable life expectancy.
Differential diagnosis
General imaging differential considerations include:
- autosomal dominant osteopetrosis
- heavy metal poisoning (e.g. lead)
- fluorosis
- melorheostosis
- hypervitaminosis D
- pyknodysostosis
- renal osteodystrophy
- fibrous dysplasia of skull or face
-<li><a href="/articles/peroneus-brevis-1">hypervitaminosis D</a></li>- +<li><a title="hypervitaminosis D" href="/articles/hypervitaminosis-d">hypervitaminosis D</a></li>
Unable to process the form. Check for errors and try again.