Among them, TLR2 and TLR4 are responsible for the recognition of bacterial peptidoglycans and LPS, respectively, and both TLR2 and TLR4 are reported to be increased in the blood and brains of PD patients (Drouin-Ouellet et al., 2014; Dzamko et al., 2017). The gene discussed is TLR4; the disease is Parkinson disease.