SYNJ1 and Parkinson disease: In the past two decades, PD etiopathogenesis has been linked with several deranged cellular mechanisms, ranging from mitochondrial impairment (PRKN, PINK1, PARK7) and ubiquitination defects (FBXO7) to dysfunction of the endolysosomal pathway (LRRK2, VPS35, VPS13C, ATP13A2) and synaptic vesicle trafficking (SNCA, RAB39B, SYNJ1, DNAJC6).