Functional Analysis of the Fibrinogen Aα Thr312Ala Polymorphism

Abstract
Background— The fibrinogen Aα Thr312Ala polymorphism occurs within the αC domain of fibrinogen, which is important for lateral aggregation and factor XIII-induced cross-linking of fibrin fibers. We have previously shown an association of Ala312 fibrinogen with poststroke mortality in subjects with atrial fibrillation and with pulmonary embolism in subjects with venous thrombosis. Methods and Results— We studied the properties of clots formed from purified Ala312 and Thr312 fibrinogen and found that Ala312 fibrinogen produces stiffer clots, associated with increased α chain cross-linking, as demonstrated by SDS-Page. On electron microscopy analysis, we found larger fiber diameters in the Ala312 clots and observed a lower number of fibers per square micrometer. The number of branch points per square micrometer was similar between genotypes. Conclusions— Our study shows that Ala312 influences clot structure and properties by increased factor XIII cross-linking and formation of thicker fibrin fibers. These fi...