TLR4 and fibrodysplasia ossificans progressiva: Pignolo R.J. and colleagues found that adiponectin which is implicated in hypoxia, inflammation, and heterotopic ossification as well as tenascin-C (an endogenous activator of innate immune signaling through the TLR4 pathway and a substrate for kallikrein-7) were highly correlated with FOP genotype, while kallikrein-7 was highly correlated with acute flare-up status in 40 FOP patients with typical ACVR gene variant [5].