Elevated HMGB1 and TLR-4 expression levels were observed in patients at more advanced stages of PD, and patients with a disease duration longer than 4 years showed significantly higher expression levels of HMGB1 and TLR-4 than those with a disease duration of less than 4 years (Yang et al., 2018b). This evidence concerns the gene HMGB1 and Parkinson disease.