Functional Gene Variations in Smokers with or without Periodontal Disease

Objectives: Functional gene variations that disrupt the delicate balance in immune response and/or repair processes predispose patients who smoke to a greater risk for periodontal disease. The aim of present study is to investigate the distribution of IL-1â, IL-10, myeloperoxidase (MPO), Plasminogen Activator Inhibitor-1 (PAI-1), PGE2, Glutathione S-transferase (GST) M1 and T1, and NAD(P)H Quinone Oxidoreductase 1 (NQO1) gene polymorphisms in smokers, with and without periodontitis.

Methods: The study consists of a case-control study of heavy smokers with or without periodontal disease. These subjects classified as “cases” or “controls” based on their periodontal status. Cases was defined as those having periodontitis > early severity (AAP classification). Control subjects were defined as those having a diagnosis of health, gingivitis, or early periodontitis (AAP Disease Classification). Blood samples were collected and then processed to obtain the buffy coat. Taqman SNP Genotyping assays were used to genotype the IL-1â (-31) (rs1143627), IL-10 (-1082) (rs1800896), IL-10 (-592) (rs1800872), and NQO1 (609) (rs1800566). Restriction Fragment Length Polymorphism analysis was used to genotype the COX-2 (-765) (rs20417), MPO (-463) (rs2333227), and PAI-1 (4G) (rs1799889). Finally, gel electrophoresis was used to determine GST-M1 and GST-T1 deletion polymorphisms using a positive PCR control (CYP-1A1). The polymorphisms' allele frequencies and genotype frequencies for GST-M1, GST-T1 were calculated using the Hardy-Weinberg equilibrium equation and direct counting. Differences in polymorphisms between the disease and control populations were calculated using 2x2 Chi Square test of homogeneity.

Results: although a higher frequency of the mutant allele was seen in the disease population for GST-T1, IL-10 (-1082) and IL-10 (-592) compared to the control population, this differences was not significant.

Conclusion: The low numbers in the control population might affect the validity of the Chi Square Test so recruitment of more control subjects is warranted.