title: Single nucleotide polymorphisms of complement component 5 and periodontitis.
abstract: OBJECTIVE
  Polymorphisms of host defence genes might increase one's risks for periodontitis. This study investigated whether tagging single nucleotide polymorphisms (SNPs) of the gene encoding complement component 5 (C5) are associated with periodontitis in a Hong Kong Chinese population.
  
  
  METHODS
  Eleven tagging SNPs of 229 patients with at least moderate periodontitis and 207 control subjects without periodontitis were genotyped using an i-plexGOLD MassARRAY mass-spectrometry system.
  
  
  RESULTS
  Genotype AG of SNP rs17611 was more prevalent in the group of periodontitis patients than in the controls (54.6% vs. 41.7%, p = 0.007). The haplotype CGCA of the haplotype block consisting of rs1035029, rs17611, rs25681 and rs992670 was significantly associated with periodontitis in a dominant model (p = 0.001). The SNP rs17611 showed high linkage disequilibrium with rs1035029, rs25681 and rs992670. Smoking was also significantly associated with periodontitis (p = 0.006).
  
  
  CONCLUSIONS
  The tagging SNP rs17611 of the C5 gene and smoking may be associated with periodontitis among the Hong Kong Chinese population.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: L
authors.initials: L
authors.lastname: Chai
authors.forename: Y-Q
authors.initials: YQ
authors.lastname: Song
authors.forename: K-Y
authors.initials: KY
authors.lastname: Zee
authors.forename: W K
authors.initials: WK
authors.lastname: Leung
mesh_terms: D000225:Adenine; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D010520:Aggressive Periodontitis / Q000235:genetics / Q000276:immunology; D016022:Case-Control Studies; D055113:Chronic Periodontitis / Q000235:genetics / Q000276:immunology; D003182:Complement C5 / Q000235:genetics*; D003596:Cytosine; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D006147:Guanine; D006239:Haplotypes; D006723:Hong Kong; D006801:Humans; D007155:Immunologic Factors / Q000235:genetics*; D007438:Introns / Q000235:genetics; D015810:Linkage Disequilibrium / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000235:genetics / Q000276:immunology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking; D055815:Young Adult
chemical_list: D003182:Complement C5; D007155:Immunologic Factors; D006147:Guanine; D003596:Cytosine; D000225:Adenine