PFD has been shown to inhibit both production and activity of TGF-β1, a cytokine that stimulates collagen synthesis and inhibits its degradation [28], and also to reduce the production of other fibrogenesis mediators, such as fibronectin and connective tissue growth factor (CTGF) [29, 30]. The gene discussed is FN1; the disease is polyostotic fibrous dysplasia.