At sites of vascular injury, the platelet collagen receptor Glycoprotein Ia/IIa (GPIa/IIa) acts as an important mediator of platelet adhesion to fibrillar collagens. Two silent polymorphisms (807C/T and 873G/A) within the glycoprotein Ia gene have been implicated in increased risk of developing thrombosis and myocardial infarction in affected individuals. To provide basis for future studies, we examined the frequency of these GPIa polymorphisms for people in Turkey. We analyzed 118 unrelated individuals for their genotypes of the GPIa gene using a multiplexed allele specific-PCR based method. The allelic frequencies were found to be 34% for 807T/873A and 66% for 807C/873G; the genotypic frequencies were 13% for 807TT/873AA, 44% for 807CT/873GA, and 43% for 807CC/873GG. (C) 2002 Wiley-Liss, Inc.