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.