Association of the Fcγ 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 (FcγR) link the humoral and cellular branches of the immune system, and regulate immune responses and inflammation. Three FcγR subclasses (FcγRIIa, FcγRIIIa, and FcγRIIIb) exhibit functional polymorphisms, which affect efficiency of FcγR-mediated functions. FcγRIIa genotypes, but not FcγRIIIa and FcγRIIIb genotypes, were differentially distributed among 107 MG patients as compared to 239 healthy controls (P≪0.01), with a relative increase of the FcγRIIa-R/R131 genotype (Odds ratio 2.4, 95% confidence interval 1.4–3.9). These data suggest that the FcγRIIa-R/R131 genotype is a marker for susceptibility to MG.