Osteopetrosis: report of a case

Osteopetrosis is a descriptive term that refers to a group of rare, heritable disorders of the skeleton characterized by increased bone density on radiographs. Osteopetrotic conditions vary greatly in their presentation and severity, ranging from neonatal onset with life-threatening complications such as bone marrow failure (e.g. classic or "malignant" ARO), to the incidental finding of osteopetrosis on radiographs (e.g. osteopoikilosis) (Zornitza Stark and Ravi Savarirayan, 2009). It is caused by the failure of osteoclaststo resorb immature bone. This leads to abnormal bone marrow cavity formation and clinically to the signs and symptoms of bone marrow failure. Impairedbone remodeling causesbony narrowing of the cranial nerve foramina which results in cranial nerve, especially optic nerve, compression. (Wilson and Vellodi, 2000) Classic ARO is characterised by fractures, short stature, compressive neuropathies, hypocalcaemia with attendant tetanic seizures, and life-threatening pancytopaenia. The presence of primary neurodegeneration, mental retardation, skin and immune system involvement, or renal tubular acidosis may point to rarer osteopetrosis variants, whereas onset ofprimarily skeletal manifestations such as fractures and osteomyelitis in late childhood or adolescence is typical of ADO. It is anticipated that further understanding of the molecular pathogenesis of these conditions will reveal newtargets for pharmacotherapy (Zornitza Stark and Ravi Savarirayan, 2009). This paper highlights a rare case of osteopetrosis in an 8 year old boy.