Objective: Genetic polymorphisms in the angiotensin-converting enzyme (ACE) and endothelial nitric oxide synthase (eNOS) are linked with expression and/or progression of renal disease. We hypothesized that polymorphisms in the genes coding for ACE and eNOS may influence the development and/or progression of systemic lupus erythematosus (SLE) and lupus nephritis given their linkage with other renal diseases.
Methods: DNA from patients with SLE (n = 227) and their age and sex matched controls (n = 275) from the Carolina Lupus (CLU) Study cohort was assessed for ACE and eNOS polymorphisms. Seventy patients had biopsy-proven lupus nephritis. Two different eNOS polymorphisms (eNOS promoter T-786(R)C nucleotide substitution and eNOS 27 base pair tandem repeat in intron 4) and the ACE insertion/deletion (I/D) polymorphism in intron 16 were examined by restriction fragment length polymorphism-polymerase chain reaction.
Results: Allele frequency of the eNOS polymorphisms varied significantly between SLE patients and controls. There was no association of these polymorphisms with lupus within ethnic groups. We found no association of the polymorphism with the development of renal disease. No association was observed for the ACE I/D polymorphism with SLE or nephritis, or with ethnicity or sex.
Conclusion: eNOS genetic polymorphisms differed significantly across ethnic groups. There was no significant increased risk of SLE and/or lupus nephritis associated with eNOS or ACE polymorphisms in either the African American or Caucasian groups compared to ethnically matched controls. These studies emphasize the need to control for ethnicity when investigating genetic polymorphisms and disease.