Perhaps unexpectedly, an initial study reported that ablation of CX3CR1 signaling in microglia led to an exacerbated rather than attenuated microglial response, significant neurotoxicity to a peripheral LPS challenge, as well as worsened neurodegeneration in experimental models of Parkinson’s disease and amyotrophic lateral sclerosis [91]. The gene discussed is CX3CR1; the disease is Parkinson disease.