PRKN and Parkinson disease: Similarly, Borsche et al. revealed that the circulating cell-free mitochondrial DNA (ccf-mtDNA)-cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) synthase (cGAS)-STING-IL-6 pathway may be responsible for Parkin/Pink1-deficiency-induced inflammation in PD [52,55].