On one hand, Kumar et al. [85] observed in a transgenic C. elegans PD model a significant down-regulation of circzip-2, a circRNA synthesized from zip-2 gene whose human ortholog codes for CCAAT-enhancer-binding protein (C/EBP), a bZIP transcription factor involved in PD by regulating α-synuclein levels [85,217]. This evidence concerns the gene SNCA and Parkinson disease.