Beyond being a biochemical marker, phosphate overload triggers NOX-derived reactive oxygen species (ROS), activates Wnt/β-catenin and TGF-β signaling, and disrupts the FGF23–Klotho axis, promoting endothelial dysfunction, vascular calcification, and left ventricular hypertrophy (LVH). The gene discussed is FGF23; the disease is endothelial dysfunction.