Inducible nitric oxide synthase gene (NOS2A) haplotypes and the outcome of hepatitis C virus infection

Genes Immun. 2004 May;5(3):183-7. doi: 10.1038/sj.gene.6364054.


Inducible nitric oxide synthase (iNOS) is an important molecule involved in the host defense against infectious agents. iNOS is encoded by the NOS2A gene and well-defined haplotypes exist with respect to this gene. We examined whether these haplotypes were associated with the outcome of hepatitis C virus (HCV) infection in 619 Caucasian patients from seven European liver centres. We observed five major haplotypes: (-277A)+(-1026G)+(-1659C): haplotype 1; (-277G)+(-1026T)+(-1659C): haplotype 2; (-277G)+(-1026G)+(-1659C): haplotype 3; (-277G)+(-1026T)+(-1659T): haplotype 4; and (-277A)+(-1026T)+(-1659C): haplotype 5. Distributions of these haplotypes are comparable with those of previous studies. Homozygotes for haplotype 2 or those with haplotypes 2/4 were more likely than those with the 1/1 (wild type) combination to have self-limiting infections (odds ratios (OR)=3.43; 95% confidence intervals (95% CI): 1.10-8.0; P=0.0206 and OR=5.15; 95% CI: 1.32-14.32; P=0.0018, respectively). Conversely, carriage of haplotype 1 was associated with the lack of self-limiting disease (OR=0.48; 95% CI: 0.27-0.83; P=0.009). The effect was mainly among males (OR=0.41; 95% CI: 0.182-0.942; P=0.031 for males, and OR=0.55; 95% CI: 0.24-1.37; P=0.136 for women). Carriage of haplotype 1 was not associated with initial response (P=0.268) or sustained response (P>0.171). Combinations of haplotypes 1/4 were more likely to respond to interferon monotherapy in comparison of initial responders to nonresponders (OR=2.25; 95% CI: 1.05-5.68; P=0.0275).

Publication types

  • Comparative Study
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antiviral Agents / therapeutic use
  • Cohort Studies
  • Disease Progression
  • Female
  • Genetic Variation*
  • Genotype
  • Haplotypes / genetics*
  • Hepacivirus / genetics*
  • Hepatitis C / enzymology
  • Hepatitis C / genetics*
  • Hepatitis C / therapy
  • Homozygote
  • Humans
  • Interferon-alpha / therapeutic use
  • Male
  • Nitric Oxide Synthase / genetics*
  • Nitric Oxide Synthase Type II
  • Odds Ratio
  • Retrospective Studies
  • Viremia / enzymology
  • Viremia / genetics
  • Viremia / therapy
  • White People


  • Antiviral Agents
  • Interferon-alpha
  • NOS2 protein, human
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type II