First, polymorphisms in C–T single-nucleotide Toll-like receptor 2 rs3804099 are associated with an increased risk of Parkinson’s disease in Han populations, especially in patients with late-onset Parkinson’s disease (124), while the recent use of the Caucasus subset for research progress markers (PPMI) cohort reported that TC heterozygotes and minor CC homozygous Toll-like receptor 2 rs3804099 significantly increased the risk of Parkinson’s disease (125), indicating that possible regional or ethnic differences play a role in the polymorphism of Toll-like receptor 2 and Parkinson’s disease. Here, TLR2 is linked to Parkinson disease.