THE 27-BP REPEAT POLYMORPHISM IN INTRON-4 OF THE ENDOTHELIAL-CELL NITRIC-OXIDE SYNTHASE GENE AND ISCHEMIC STROKE IN A JAPANESE POPULATION

Endothelium-derived nitric oxide formed by endothelial constitutive ni tric oxide synthase (ecNOS) mediates endothelium-dependent vasodilatio n and antithrombotic action. We analyzed the distribution of a polymor phism of ecNOS (27-bp repeat in intron 4) in 127 ischemic stroke patie nts (18 with atherothrombotic, 58 with lacunar, and 51 with silent lac unar stroke) and 91 control subjects. When we assigned the four repeat s as allele a, and five repeats as allele b, there was no significant difference between the genotype distribution and allele frequencies in the stroke group and in the control group (0.862 versus 0.868 for the b allele frequency). Moreover, there was also no significant differen ce in the genotype distribution or allele frequencies among the three stroke subgroups (b allele frequency: 0.889 for atherothrombotic strok e; 0.862 for lacunar stroke; 0.853 for silent lacunar stroke). These f indings suggest that there is no overt association between this ecNOS gene polymorphism and ischemic stroke. We found no evidence that this polymorphism may be a genetic factor for the onset of cerebrovascular disease in this Japanese population. (C) 1998 Lippincott-Raven Publish ers.