The variable number of tandem repeat polymorphism in the P-selectin glycoprotein ligand-1 gene is not associated with coronary heart disease.

Genes involved in inflammatory processes are candidates for predisposition to prothrombotic syndromes. The variable number of tandem repeat (VNTR) polymorphism in the P-selectin glycoprotein ligand (PSGL)-1 gene has been associated with ischemic cerebrovascular disease but not with coronary heart disease (CHD). We assessed the effect of the VNTR polymorphism on CHD in two independent case/control studies. In the first study 281 CHD patients and 397 healthy blood donors were genotyped for the VNTR alleles in PSGL-1. The prevalence of homozygous carriers of the PSGL-1 VNTR allele with 15 repeat units was significantly higher in the CHD patients (5.3% vs. 1.5%) than in controls, suggesting an effect of this marker in CHD. To validate the findings genotyping was performed in a second study including 2,578 CHD patients, 731 patients without CHD, and 1084 healthy blood donors. The larger case control study had a power of 99.9% to detect the initially observed difference but failed to confirm the putative role of PSGL-1 VNTR polymorphism in CHD. Frequencies of the PSGL-1 VNTR 15 repeats for homozygous carriers were 2.2% in healthy blood donors, 2.3% in patients without CHD and 2.7%, in CHD cases, respectively. These results demonstrate that the PSGL-1 VNTR polymorphism is not a genetic risk factor for CHD. Adequately powered studies are prerequisites to obtain reliable results about genotype-phenotype relationships of new candidate genes in complex diseases.

Polymorphisms in the P-selectin (CD62P) and P-selectin glycoprotein ligand-1 (PSGL-1) genes and coronary heart disease.

P-selectin and its ligand, PSGL-1, are cell adhesion molecules that facilitate interaction of platelets, leukocytes and endothelial cells. Polymorphisms of these genes have been reported to be associated with coronary heart disease (CHD). In the present study, we characterized the entire coding regions of P-selectin and PSGL-1 genes in CHD patients and healthy controls. The 17 exons of the P-selectin gene and exon 2 of the PSGL-1 gene were screened for single nucleotide polymorphisms (SNPs) by exon re-sequencing in 88 CHD patients and 96 controls. For rapid genotyping of the SNPs we developed PCR techniques with sequence-specific primers (PCR-SSP). By using PCR-SSPs we genotyped 261 CHD patients and 214 controls for 5 SNPs in P-selectin and 2 SNPs in PSGL-1. In addition to the already described SNPs in P-selectin (S290N, N562D, V599L and T715P), we identified a novel SNP in exon 5 (V168M). The P-selectin 715P allele was more frequent among CHD patients with hypercholesterolemia compared to patients with normal cholesterol levels. A SNP (M621) in the PSGL-1 gene was found close to the P-selectin binding site and the 621 allele revealed a higher prevalence in the control group indicating a protective effect of the mutation. The molecular characterization of P-selectin and PSGL-1 in a case-control study including CHD patients and healthy controls revealed evidence for association of the genes with development of the disease. However, the functional role of the gene variants should be elucidated by further experimental data.