TGFB1 and fibrodysplasia ossificans progressiva: Recently, de Ruiter et al. discovered that TGF-β1 stimulates the generation of activin A in dermal fibroblasts obtained from FOP patients, as evidenced by an increase in the inhibin subunit beta A (INHBA) gene and protein expression levels, functioning as an upstream activator of activin A generation, specifically in FOP [94].