Endothelial nitric oxide synthase gene polymorphism is associated with Legg-Calvé-Perthes disease

The aim of this study was to assess the association of 27-bp variable number tandem repeat (VNTR) polymorphism in intron 4 and G894T polymorphism in exon 7 of the endothelial nitric oxide synthase (eNOS) gene with Legg-Calvé-Perthes disease (LCPD), and to provide a scientific basis for further research into the pathogenic mechanism. A total of 80 patients with LCPD and 100 healthy subjects were recruited in this case-control study. The 27-bp VNTR and G894T polymorphisms of the eNOS gene were genotyped using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively, followed by agarose gel electrophoresis and DNA sequencing. Allelic and genotypic frequencies were computed in the two groups and subjected to statistical analysis. For the 27-bp VNTR polymorphism, individuals with LCPD showed a higher frequency of the ab genotype [27.5 vs. 14%; odds ratio (OR), 2.33; 95% confidence interval (CI), 1.10-4.92; P=0.024]. For the G894T polymorphism, the LCPD case group showed a higher frequency of the heterozygous genotype GT than the healthy control group (35 vs. 17%; OR, 2.67; 95% CI, 1.33-5.36; P=0.005). The results indicate that these eNOS gene polymorphisms may be a risk factor for LCPD. The 27-bp VNTR polymorphism in intron 4 and G894T polymorphism in exon 7 may be involved in the etiology of LCPD.