The variable number of tandem repeat polymorphism of platelet glycoprotein Ibalpha and risk of coronary heart disease.

Glycoprotein (GP) Ib-IX-V complex plays an important role in formation of platelet-fibrin clot at the area of damaged vessel wall. One polymorphism of GP Ibalpha, the main component of GP Ib-IX-V complex, is due to variable numbers of tandem repeats (VNTRs) in the macroglycopeptide region of this molecule. We studied the association between the presence of different VNTR alleles of GP Ibalpha and the frequency of coronary heart disease (CHD) among individuals recruited to a large community-based case-cohort study (Atherosclerosis Risk in Communities [ARIC] study). We found that the distribution of VNTR alleles of GP Ibalpha is different among whites and African Americans. The B allele (with 3 repeats) of GP Ibalpha is relatively more common among African Americans compared with whites. In African Americans, the CC genotype (homozygous with 2 repeats) is associated with a lower risk of CHD events than all other genotypes.