PRKN and Parkinson disease: In Parkinson’s disease, circSLC8A1 is linked to oxidative stress via miR-128/miR-132; circ_0004381 and circ_0017204, early PD biomarkers; circ_0085869, circ_0004381, and circ_0090668, distinguishing disease stages; circEps15, which promotes dopaminergic recovery via miR-24/PINK1-PRKN mitophagy; circSV2b, restoring dopamine synthesis via miR-5107-5p/Foxk1/Akt1; and circPANK1 and circSNCA, which boost α-synuclein by sponging miR-7, driving neurotoxic aggregation.