title: Association of Fcgamma receptor IIa genotype with chronic periodontitis in Caucasians.
abstract: BACKGROUND
  Functional polymorphisms of immunoglobulin G (IgG) Fc receptors IIIa and IIIb (FcgammaRIIIa and FcgammaRIIIb) have been shown as risk factors for periodontitis. The aim of this study is to examine whether FcgammaRIIa polymorphism is associated with a disease risk as well.
  
  
  METHODS
  Baseline periodontal and general health examinations were carried out on 1,221 Caucasian adults. From these, 422 subjects with moderate to severe, or little or no periodontal disease were assigned to two groups according to their mean clinical attachment loss (CAL). Subjects with mean CAL > or = 2.94 mm were diagnosed with chronic periodontitis (n = 213, 62 never-smokers and 151 smokers). Subjects with mean CAL < or = 1.77 mm were considered as having little or no periodontal disease and designated as controls (n = 209, 125 never-smokers and 84 smokers). The FcgammaRIIa genotype for three bi-allelic polymorphisms (FcgammaRIIa-R/ R131, R/H131, and H/H131) was determined by means of allele-specific polymerase chain reactions.
  
  
  RESULTS
  The distribution of FcgammaRIIa genotype between the patient and control groups was significantly different, with enrichment of the high ligand-binding genotype FcgammaRIIa-H/H131 in the patients (patients versus controls: 36.6% versus 25.4%; P = 0.04). Multivariate logistic regression model demonstrated that subject age and gender, smoking, and the FcgammaRIIa genotype were significantly associated with severity of chronic periodontitis. For smokers, a significant over-representation of FcgammaRIIa-H/H131 in the patient group compared to the control group (patients versus controls: 35.1% versus 19.0%; P = 0.03). Additionally, smokers with FcgammaRIIa-H/H131 exhibited significantly greater mean CAL (mean +/- SE: 3.44 +/- 0.16 mm) than those with FcgammaRIIa-R/H131 (2.91 +/- 0.14 mm) and R/R131 (2.82 +/- 0.16 mm) (P = 0.04). There was no association between FcgammaRIIa genotype and the disease susceptibility or severity in subjects who had never smoked.
  
  
  CONCLUSIONS
  Our results suggest that the FcgammaRIIa-H/H131 genotype may be associated with chronic periodontitis risk (and disease severity) in Caucasian smokers. Further studies with families and studies of mechanisms are necessary to help establish the extent to which this is a genetic determinant of periodontal diseases.
authors.affiliation: Division of Periodontology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Kouji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Sara
authors.initials: S
authors.lastname: Grossi
authors.forename: Alex W
authors.initials: AW
authors.lastname: Ho
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Genco
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Yoshie
authors.forename: Ernesto
authors.initials: E
authors.lastname: De Nardin
mesh_terms: D000367:Age Factors; D000368:Aged; D000483:Alleles; D015703:Antigens, CD / Q000235:genetics*; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010518:Periodontitis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D017452:Receptors, IgG / Q000235:genetics*; D012737:Sex Factors; D012907:Smoking; D044465:White People / Q000235:genetics*
chemical_list: D015703:Antigens, CD; C080568:Fc gamma receptor IIA; D017452:Receptors, IgG