Background: Nitric oxide (NO) is synthesized by endothelial cell NO synthase (ecNOS) on vascular endothelium, and it plays a key role in the regulation of blood flow and pressure. A polymorphism of the ecNOS gene was recently shown to be associated with the development of cardiovascular disease.
Patients and methods: We investigated the ecNOS gene polymorphism in 68 Japanese patients with IgA nephropathy (IgAN) and 134 normal controls.
Results: The genotype distributions were not different between the normal controls and the IgAN patients (ecNOS4b/b: ecNOS4b/a: ecNOS4a/a = 106:27:1 and 50:18:0, respectively). There was no significant difference in the renal histopathological grading between the patients with ecNOS4b/a and ecNOS4b/b. However, among the subgroup of patients whose duration of illness was two or more years, the advanced histopathological grading was more frequent in the patients with the ecNOS4b/a genotype (than in those with the ecNOS4b/b (p = 0.04)). The incidence of hypertension was also higher in the patients with the ecNOS4b/a genotype (50% in ecNOS4b/a versus 12% in ecNOS4b/b, p = 0.04).
Conclusion: These results suggest that the ecNOS4b/a genotype (or ecNOS4a allele) of the ecNOS gene polymorphism may be involved in the progression of IgAN.