Malignant infantile osteopetrosis is a rarely seen severe disorder which appears early in life with general sclerosis of the skeleton. It is caused by functionally defective osteoclasts which fail to resorb bone. Affected infants can exhibit a wide spectrum of clinical manifestations including impaired hematopoiesis, hepatosplenomegaly, visual impairment, and hypocalcemia. With the exception of...

In the rare hereditary bone disorder of osteopetrosis, reduced bone resorption function leads to both the development of densely sclerotic fragile bones and progressive obliteration of the marrow spaces and cranial foramina. Marrow obliteration, typically associated with extramedullary hemopoiesis and hepatosplenomegaly, results in anemia and thrombocytopenia; and nerve entrapment accounts for ...

OBJECTIVES To inform otolaryngologists about upper airway obstruction requiring tracheotomy and other otolaryngological manifestations of malignant infantile osteopetrosis (MIOP) and to discuss pathophysiological features, management, and new treatment strategies in MIOP. DESIGN Ongoing case series combined with a retrospective chart review. SETTING International tertiary pediatric hospital...

Various genetic conditions produce dysfunctional osteoclasts resulting in osteopetrosis or osteosclerosis. These include human pycnodysostosis, an autosomal recessive syndrome caused by cathepsin K mutation, cathepsin K-deficient mice, and mitf mutant rodent strains. Cathepsin K is a highly expressed cysteine protease in osteoclasts that plays an essential role in the degradation of protein com...

Mitochondrial complex I (CI) deficiency is associated with multiple neurological and metabolic disorders. However, its effect on innate immunity and bone remodeling is unclear. Using deletion of the essential CI subunit Ndufs4 as a model for mitochondrial dysfunction, we report that mitochondria suppress macrophage activation and inflammation while promoting osteoclast differentiation and bone ...

Pycnodysostosis is a rare genetic disorder and was first described in 1962 by Maroteaux and Lamy. The incidence of this anomaly is estimated to be 1.7 per 1 million births. The principal characteristics of this disorder are short stature, prominent eyes with blue sclera, beaked nose, cranial dysplasia, exposed fontanelles and cranial sutures, clavicular dysplasia, total/partial dysplasia of the...

Malignant infantile osteopetrosis is a rare inherited disease of bone metabolism, in which osteoclast dysfunction and diminished turnover lead to diffuse sclerosis with obliteration the medullary cavities narrowing skull base neural foramina. We report case malignant marrow failure optic atrophy that co-occurred hypophosphatasia, another disease, 6-year-old boy. Key imaging signs these diseases...

Presentation characteristics were reviewed in 14 children from 12 families with malignant infantile osteopetrosis seen at two large referral centres for bone marrow transplantation. Children from six of these families presented initially with symptoms of hypocalcaemia. These comprised early or late neonatal convulsions in six cases (corrected serum calcium < 1.5 mmol/l), and vomiting and irrita...