Vascular/endothelial contributors that narrow the hemodynamic response window—reduced nitric oxide bioavailability and heightened endothelin-1/Rho-kinase tone—support risk-factor optimization in parallel with neurogenic care without overstating causality in MS (Ritchie and Sullivan, 2011; Zanin-Silva et al., 2021). The gene discussed is EDN1; the disease is myeloid sarcoma.