A different hypothesis about the development of vasculopathy, proposes that the accumulation of endothelial Gb3 causes a dysregulation of the enzyme nitric oxide endothelial synthase (eNOS) with the consequent formation of oxidant species derived from NO, which could be direct markers of vasculopathy in FD [27,28,29,30,31,32,33,34]. The gene discussed is NOS3; the disease is Fabry disease.