Although RBD has only about a 30–50% chance of occurring in PD, research has shown that over 90% of individuals with RBD symptoms eventually develop synuclein-related neurodegenerative diseases, including PD, underlines the intricate and diverse trajectories within the PD journey (Howell and Schenck, 2015; Galbiati et al., 2019). Here, SNCA is linked to Parkinson disease.