Exposure to polystyrene MPs and NPs has been shown to accelerate dopaminergic neuron degeneration and induce PD-like motor dysfunction in mouse models, particularly those involving the A53T alpha-synuclein mutation or direct intestinal exposure pathways (Liang et al., 2025; Bai et al., 2025; Liang et al., 2022; Liang et al., 2024c). Here, SNCA is linked to Parkinson disease.