These findings were corroborated in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin)–induced murine model of PD where the genetic absence of TLR4 signaling protected the mice from neurodegeneration, highlighting the primary role of TLR4 in PD development [83]. The gene discussed is TLR4; the disease is Parkinson disease.