Variability within the human iNOS gene and Achilles tendon injuries: Evidence for a heterozygous advantage effect

Charlotte Brookes, William J. Ribbans, Louis Y. El Khoury, Stuart M. Raleigh

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
3 Downloads (Pure)


Objectives: The aim of this case control genetic association study was to explore whether two variants within the inducible nitric oxide synthase (iNOS) gene, rs2779249 (C/A) and rs2248814 (A/G), influenced the risk of Achilles tendinopathy in a British population. Design: Candidate gene, case control association study. Method: We recruited 145 individuals diagnosed with Achilles tendon pathology and 132 asymptomatic controls. All participants were genotyped for the iNOS variants using qPCR and significant associations were discovered using a combination of Chi squared and ANOVA type analysis. Results: The CA genotype of the iNOS rs2779249 variant was protective and conformed to a heterozygous advantage model of inheritance as it was overrepresented in the control participants (p = 0.009). In sex specific analysis the protective association persisted in male participants (p = 0.016) but not in females. Unlike the rs2779249 variant, the rs2248814 variant was not associated with Achilles tendinopathy or Achilles tendon rupture. Conclusion: The rs2779249 CA genotype within the human iNOS gene appears to protect individuals from Achilles tendinopathy. This study further supports a genetic contribution to modifying the risk of Achilles tendon problems. The study also infers an important role for nitric oxide in tendon healing and/or degradation.

Original languageEnglish
Pages (from-to)342-346
Number of pages5
JournalJournal of Science and Medicine in Sport
Issue number4
Early online date8 Nov 2019
Publication statusPublished - Apr 2020


  • Achilles tendon
  • Apoptosis
  • Genetics
  • Inflammation
  • Nitric oxide

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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