Abstract: Objective：To investigate the relationship between Mitochondrial DNA(mtDNA) SNP and the severity of periodontitis. Methods: In the study, 227 subjects in a community of Beijing received questionnaire interview, periodontal examination and biochemical laboratory examination in 2005. The designed primer was used to amplify the specific mtDNA fragments with PCR, and sequence the PCR products. Finally, the relationship between severity of chronic periodontitis and mtDNA SNP at site 10398 was analyzed. Results: The number of the subjects included at mtDNA site 10398 was 227. The G allele frequency in the metabolic syndrome(MS) subjects was significantly higher than that in the non MS subjects ［80（70.2%） vs. 34（29.8%），P=0.039］. The result of Logistic regression showed that the subjects with G allele had higher risk of MS than the subjects with A allele(OR=1.77，95%CI=1.02-3.06, P=0.042). But there was no significant relationship between the 10398 A→G SNP and severity of periodontitis. Conclusion: In this population, mtDNA SNP 10398 A→G may be associated with MS. However, there was no relationship between the 10398 A→G SNP and severity of chronic periodontitis.

Key words: Metabolic syndrome, Periodontitis, DNA,mitochondria, Polymorphism, single nucleotide