Interleukin-1 receptor antagonist gene polymorphism and gingivitis in children

Aim:  To investigate the role of the polymorphism of a variable numbers of tandem repeats of interleukin-1 receptor antagonist gene (IL-1RN) on gingivitis in children. Materials and methods:  A total of 146 Caucasian subjects (98 subjects with gingivitis and 48 controls) aged 8–12 years, were enrolled. Plaque and Calculus Indices were recorded to assess the oral hygiene. Gingival and Bleeding on Probing Indices were used to identify patients with gingivitis. DNA was extracted from epithelial cells of the cheek. Normal polymerase chain reaction was used for IL-1Ra genotyping. Results:  A significant association was observed between IL-1Ra gene polymorphism and gingivitis in children (P = 0.008). The IL-1RN*2 allele (A2) was significantly more frequent in controls (37%vs 22% in children with gingivitis). In addition, the carriage of A2 seemed to be protective against gingivitis, and it was more frequent in controls (60%vs 40% in children with gingivitis, P = 0.008). Moreover, multiple logistic regression analysis showed that the association between IL-1Ra gene polymorphism and gingivitis in children remained significant (P = 0.014) regardless of the significant influence of plaque (P = 0.013). Conclusion:  IL-1Ra gene polymorphisms could have an active role in the pathogenesis of gingivitis in Caucasian children and IL-1RN*2 allele could be a protective marker against gingivitis.