Vitronectin, is a 75-kD glycoprotein in plasma and tissue. (S-protein is not to be confused with protein S.) A multifunctional protein, it promotes attachment and spreading of animal cells in vitro, inhibits cytolysis by the complement C5b-9 complex, and modulates antithrombin III-thrombin action in blood coagulation. The primary structure of vitronectin has been deduced from the sequence of its cloned cDNA. Polymorphism of vitronectin of plasma has been demonstrated. Sun and Mosher (1989) demonstrated that the frequencies are different in Orientals and Caucasians. By use of high resolution fluorescence in situ hybridization (FISH), Fink et al. (1992) mapped the VTN gene to 17q11. The localization was confirmed by cohybridization with a centromere-specific alphoid probe.