Association of the Fc gamma receptor IIA-R/R131 genotype with myasthenia gravis in Dutch patients.

Myasthenia gravis (MG) susceptibility is partially determined by allelic heterogeneity of immune-modulatory genes. IgG receptors (FcgammaR) link the humoral and cellular branches of the immune system, and regulate immune responses and inflammation. Three FcgammaR subclasses (FcgammaRIIa, FcgammaRIIIa, and FcgammaRIIIb) exhibit functional polymorphisms, which affect efficiency of FcgammaR-mediated functions. FcgammaRIIa genotypes, but not FcgammaRIIIa and FcgammaRIIIb genotypes, were differentially distributed among 107 MG patients as compared to 239 healthy controls (Pz.Lt;0.01), with a relative increase of the FcgammaRIIa-R/R131 genotype (Odds ratio 2.4, 95% confidence interval 1.4-3.9). These data suggest that the FcgammaRIIa-R/R131 genotype is a marker for susceptibility to MG.

Fcgamma receptor polymorphisms in relation to periodontitis.

OBJECTIVES: Evidence suggests functional relevance for polymorphisms in FcgammaR in relation to inflammatory and infectious diseases. The present aim was to investigate genetic polymorphisms in three FcgammaR in relation to susceptibility and severity of periodontitis. MATERIAL AND METHODS: The study population consisted of 68 periodontitis patients and 61 controls (Northern European Caucasian background, mean ages 44 and 42 years, respectively). Among the patients, 12 subjects were diagnosed with aggressive periodontitis (AgP) and 56 individuals were diagnosed with chronic periodontitis (CP). Radiographic bone levels were scored for all teeth in the patients. Subjects were typed for the following genes (alleles): FcgammaRIIa (R131 or H131), FcgammaRIIIa (V158 or F158) and FcgammaRIIIb (NA1 or NA2). RESULTS: Hardy-Weinberg equilibrium criteria were fulfilled for the different genotypes at the three genes investigated. The frequency of the FcgammaRIIIa-V158 allele in the patient population (53%) was higher than in the control group (39%) (OR 1.73 [1.06-2.85], p=0.034). The V158 carriage rate in AgP was even higher (63%). The frequency of the FcgammaRIIa-H131 allele in the total periodontitis population was 58%; for AgP this was 79%, compared with 51% in the control population (OR 3.68 [1.29-10.5], p=0.013). Also, the frequency of the FcgammaRIIa-H/H131 genotype was significantly higher in AgP patients than in controls (OR 9.07 [1.29-63.56], p=0.026, adjusted for smoking status and other potential confounders). Moreover, patients with the FcgammaRIIa-H/H131 genotype had more severe radiographic bone loss than patients with the other FcgammaRIIa genotypes. CONCLUSION: The current study of relative small sample size suggests that the FcgammaRIIa-H/H131 genotype may be a putative susceptibility and severity factor, and the FcgammaRIIIa-V158 allele a putative susceptibility factor for periodontitis in Northern European Caucasians. These results need further verification and the biological importance of these findings needs further investigation.