Background: Endothelial nitric oxide synthase (eNOS) is involved in key steps of immune response. The aim of the present study was to evaluate genotype distribution and genotype-phenotype association in periodontal disease regarding Glu298Asp polymorphism of the eNOS gene.

Methods: A total of 272 subjects were included into the study. Genomic DNA was obtained from the peripheral blood of 51 chronic periodontitis (CP) patients, 48 generalized aggressive periodontitis (GAgP), and 173 reference controls. Polymerase chain reaction (PCR) amplification and subsequent BanII restriction fragment length polymorphism (RFLP) analysis were used to detect eNOS Glu298Asp polymorphism. Probing depth, clinical attachment loss, plaque accumulation, and bleeding on probing (BOP) were recorded. The data were analyzed by the χ² test, logistic regression, and Mann-Whitney U test.

Results: The distributions of eNOS Glu298Asp genotypes and alleles were similar among study groups. Subjects with the Asp allele (Asp+) were statistically higher in the CP group compared to the control group (odds ratio [OR] = 1.957; 95% confidence interval [95% CI] = 1.038 to 3.689). In the GAgP group, BOP (%) was significantly higher in patients with the 298Asp allele (Asp+) compared to patients without the Asp allele (Asp−) (P = 0.015).

Conclusions: The present study showed that eNOS Glu298Asp polymorphism is associated with BOP in GAgP patients. Moreover, the 298Asp allele of the eNOS gene might be related to CP in the Turkish population.