Molecular, Phenotypic Aspects and Therapeutic Horizons of Rare Genetic Bone Disorders

Figure 5

Schematic diagram of the pathogenesis of FOB: mutation of the Alk2 subunit (blue arrow) of BMP receptor I leads to constitutive phosphorylation of the downstream regulated-smad1, -5, and -8 that associate with smad4. Multimeric smad complex translocates to the nucleus and positively regulates several transcription factors responsible for osteoblast differentiation and bone formation.