Definition: an inherited, diffuse bone disease that results in sclerotic thickening of the skeleton on radiological examination
Etiology: infancy or early childhood
Pathophysiology: gene mutations → inability of osteoclasts to generate acidic environment in the bone matrix → bone resorption with preserved osteoblastic function → overgrowth of bone with pathological bone composition
Clinical features
Recurring pathological fractures (osteopetrotic bone tissue is very dense but brittle)
Cranial nerve disorders (e.g., palsies) due to hyperostosis and stenosis of the cranial nerve foramina
Hepatosplenomegaly due to extramedullary hematopoiesis
Diagnostics
X-ray: symmetrical, homogenous, sclerotic thickening of both cortical and trabecular bone (stone bone)
Calcium levels may be normal or low (especially in severe form, e.g., type I osteopetrosis).
Therapy
Bone marrow transplant (potentially curative treatment): Functional osteoclasts may develop from unimpaired monocytes deriving from transplanted stem cells.
