Moreover, the anti-inflammatory and gut barrier-promoting effects of probiotic administration are attributed to TLR2-dependent mechanisms (Kuugbee et al., 2016; Paveljšek et al., 2020), and thus further studies are required to investigate if probiotic administration to people with pro-inflammatory TLR2 SNPs has enhanced benefit for PD symptoms. This evidence concerns the gene TLR2 and Parkinson disease.