Evaluation of Novel Platelet Polymorphisms in Stroke. Dichotomic Effect of rs5443 in GNB3

Our group recently characterized two single-nucleotide poly-morphisms (SNPs), rs4366150 and rs1787566, on the genes encoding lysophosphatidic acid receptor-1 (LPAR1) and my-osin VB (MYO5B), respectively, which are associated with platelet reactivity, in a cohort of 286 healthy children. 1 Furthermore , the recently identified SNPs rs5443 (on the gene encoding guanine nucleotide binding protein 3, GNB3) and rs3737224 (on the gene encoding platelet endothelial aggre-gation receptor 1, PEAR1) 2,3 may also be considered as potential new genetic factors implicated in platelet function. However, the role of these SNPs in thrombosis or hemorrhage disorders has either not been addressed, or is still controversial. Given the functional effect of the four aforementioned SNPs, we aimed to determine their potential role in 1) the development of thrombosis in patients with ischemic stroke (IS) or 2) bleeding in patients with intracranial hemorrhage [subarach-noid hemorrhage (SAH) and intracerebral hemorrhage (ICH)]. For this purpose, the presence of the four SNPs was determined in consecutive patients who survived an IS and in patients who suffered from an intracranial hemorrhage. The co-hort with IS according to the Trial of ORG 10172 in Acute Stroke Treatment criteria were patients enrolled in the Unit of Neurology in Reina Sofia Hospital (Murcia, Spain). We also recruited 611 healthy controls from the general population from blood donors (n=377) and traumatology and ophthalmol-ogy patients undergoing minor outpatient surgery (n=234). Cohorts with SAH and ICH were enrolled over a 3-year period and are described in a previous report from our group. 4 All subjects were Caucasians and gave their informed consent to enter the study, which was approved by the local Ethics Committee and was performed according to the Declaration of Helsinki. Genomic DNA was isolated from whole blood samples according to standard procedures, and DNA was amplified using Taqman probes from Life Technologies (Madrid, Spain). Genotyping of the different cohorts for the different SNPs showed that they were all in Hardy-Weinberg equilibrium (not shown). The general characteristics of patients and controls are given in Table 1. The univariate analyses revealed no association (p>0.05) between the presence of rs4366150 (LPAR1), rs1787566 (MYO5B), and rs3737224 (PEAR1), and the development of IS, SAH, or ICH (Table 1). Nevertheless, there was a trend toward significance for the rs5443 (T allele) SNP in GNB3 as a risk factor in the development of IS (p=0.087) and as a protective factor in SAH (p=0.071). No association between rs5443 (T allele) and …