[Genetic basis for skeletal disease. Molecular advances in sclerosing bone disorders].

Sclerosing bone disorders are caused by impaired osteoclastic bone resorption or increased bone formation. Osteopetrosis, a representative disease caused by impaired bone resorption, is a heterogeneous disease, and various molecules have been recently identified to be responsible. In infantile malignant osteopetrosis, there are osteoclast-rich and osteoclast-poor forms, which are caused by dysfunction of osteoclasts and impaired osteoclastogenesis, respectively. As to the sclerosing bone diseases related to the increased bone formation, molecular analyses of these disorders uncovered the involvement of TGF-beta and Wnt signaling in the regulation of bone mass.