FCGR2A and Parkinson disease: In vivo studies are sparse, but in vitro studies have provided further evidence of a critical role of FcγR in neuronal damage microglia co-cultured with dopaminergic neurons coated with IgG from the sera of PD patients, results in increased levels of pro-inflammatory cytokines (TNFα), reactive oxygen species synthesis, and the initiation of cell death in co-cultured neurons.