Objective: To assess the influence of endothelial nitric oxide synthase (eNOS) polymorphisms in the susceptibility to giant cell arteritis (GCA).
Methods: We studied 57 patients with biopsy-proven GCA diagnosed at the Rheumatology Division of Hospital Xeral-Calde and 117 ethnically matched controls. Patients and controls were genotyped by PCR for a variable number tandem repeat polymorphism in intron 4, a T/C polymorphism at position -786 in the promoter region, and a polymorphism in exon 7 (298Glu/Asp or 5557G/T) of the eNOS gene.
Results: No differences in allele or genotype frequencies for individual polymorphisms were observed between patients with GCA and controls. However, when haplotype frequencies for the combination of the 3 eNOS polymorphisms were estimated, a significant increase in the frequency of haplotype C/1/T and a significant decrease in the frequency of haplotype C/1/G were observed in GCA patients compared to controls (p = 0.04, OR 1.8, 95% CI 1.0-3.3; p = 0.02, OR 0.3, 95% CI 0.1-0.8, respectively).
Conclusion: Significant differences in eNOS haplotype frequencies between GCA patients and controls may indicate a role for these polymorphisms in the susceptibility to this condition.