C19orf25 is a gene of unknown function located on chromosome 19 that functions in the regulation of intracellular STING trafficking. Through genome-wide optical pooled screening of 45 million cells, C19orf25 was identified in a functional cluster with USE1, a protein mediating Golgi-to-endoplasmic reticulum transport 1. Loss of C19orf25 enhances STING signaling, indicating it normally acts as a negative regulator of the innate immune sensor STING 21. This suggests C19orf25 likely functions in promoting STING degradation or facilitating its exit from the Golgi apparatus, similar to other trafficking regulators identified in the screen. Beyond its role in STING regulation, C19orf25 has emerged as a potential biomarker for Parkinson's disease, appearing among five differentially methylated genes in cerebrospinal fluid cell-free DNA that correlate with PD diagnosis and specific phenotypic features 3. The altered methylation patterns of C19orf25 in PD patients suggest possible involvement in neuroinflammatory processes. Despite these functional insights, the precise molecular mechanisms by which C19orf25 regulates STING trafficking and its contribution to neurodegeneration remain to be elucidated.