No association between a polymorphism of the endothelial constitutive nitric oxide synthase gene and ischemic stroke in a japanese population

Endothelial-derived nitric oxide (NO) formed by endothelial constitutive nitric oxide synthase (ecNOS) mediates vasodilation and antithrombotic action. A close association between a polymorphism of ecNOS gene (27-bp repeats in intron 4) and onset of coronary artery disease in Caucasian was reported and a close association between onset of angiopathy and this polymorphism was suggested. We analyzed this polymorphism in 127 ischémie stroke patients (18 atherothrombotic, 58 lacunar, 51 silent lacunar) and 91 healthy subjects. We identified 2 alleles (denoted as "allele a" for 4-repeats and "allele b" for 5-repeats), and grouped the subjects into 3 genotypes (a/a, b/a, b/b). There was no significant difference in the genotype distribution and allele frequencies between the stroke and control groups. There was also no significant difference in the genotype distribution and allele frequencies between the stroke types. From these findings, we could not find the evidence that this ecNOS gene polymorphism may be a genetic factor for the onset of cerebrovascular disease.