[Cytokines in bone diseases. Wnt signaling and osteoporosis-pseudoglioma syndrome].

Wnt signaling system plays essential roles in development, cancer and bone metabolism. Canonical wnt signaling, which involves wnt ligands, receptor named frizzled and co-receptors LRP5/6, beta-catenin and transcription factors named LEF/TCF is well characterized and its defect causes bone abnormalities. The loss-of-function type of the LRP5 gene mutation is responsible for osteoporosis-pseudoglioma syndrome. In addition, the LRP6 gene mutation leads to osteoporosis and metabolic syndrome. Thus, wnt signaling system is one of determinant factors for bone mineral density.