Objective: To assess the contribution of 2 polymorphisms within the inducible nitric oxide (NOS2A) promoter region to the susceptibility to Henoch-Schönlein purpura (HSP), and to determine if implications exist with severe systemic complications of HSP, in particular with severe renal involvement and permanent renal dysfunction (renal sequelae).
Methods: Fifty-eight patients from Northwest Spain with primary cutaneous vasculitis classified as HSP were studied. All patients were required to have had at least 2 years' followup. Patients and ethnically matched controls (n=251) were genotyped by PCR based techniques for a multiallelic (CCTTT)n and for the biallelic TAAA repeat in the promoter region of the NOS2A gene.
Results: HSP patients exhibited a significantly increased frequency of the NOS2A short (8-11) CCTTTn alleles (OR 1.64, 95% CI 1.09-2.47, p=0.017) and genotypes (OR 3.59, 95% CI 1.79-7.20, p=0.0002) compared to controls, particularly when patients with nephritis were compared with controls. However, when the NOS2A TAAA repeat polymorphism was assessed, no differences were found.
Conclusion: Significant differences in the NOS2A promoter polymorphism allele and genotype frequency between HSP patients and controls suggest a potential role for this gene in the susceptibility to HSP and in the development of nephritis.