Besides, the increase of staurosporine biosynthesis was also distinguishable between PD without RBD and NC, while other 5 elevated pathways (steroid degradation, staurosporine, renin secretion, mannose type O-glycan biosynthesis, other types of O-glycan biosynthesis and Fc gamma R-mediated phagocytosis) and 1 decreased pathway (biotin metabolism) were observed specifically in PD without RBD vs. NC, not in PD with RBD vs. NC (Fig. 3C). Here, REN is linked to Parkinson disease.