Mice deficient in the urokinase-type plasminogen activator receptor (uPAR), which functions with its ligand urokinase-type plasminogen activator (uPA) in the plasminogen activation system, exhibit impaired fibrinolysis and spontaneously develop vasculopathy and fibrosis, closely mirroring human SSc. The gene discussed is PLAU; the disease is systemic sclerosis.