Role of the 807 C T polymorphism of the alpha(2) gene in platelet GP Ia collagen receptor expression and function - Effect in thromboembolic diseases

The variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of,the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of th is polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a signific ant association between the 807 C/T polymorphism and the platelet GP Ia den sity. The T allele correlated with high number of GP Ia molecules on platel et surface. In addition, we observed a similar association of this polymorp hism with the expression of this protein in other brood cell types. The pla telet responsiveness to collagen was determined by "in vitro" analysis of t he platelet activation and aggregation response. We found no significant di fferences in these functional platelet parameters according to the 807 CIT genotype. Finally, results from 3 case/control studies involving 302 consec utive patients (101 with coronary heart disease, 104 with cerebrovascular d isease and 97 with deep venous thrombosis) determined that the 807 CIT poly morphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.