LRRK2 and Cognitive impairment: While PD patients carrying mutations of the β-glucocerebrosidase gene (GBA) have more severe dysautonomic symptoms and RBD than patients with idiopathic PD and more frequent cognitive impairment (Zhang et al., 2018; Carandina et al., 2022), PD patients with mutations in the LRRK2 gene encoding leucine-rich repeat kinase 2 (LRRK2) protein show much lower frequency of RBD (Pont-Sunyer et al., 2015; Fernández-Santiago et al., 2016), less OH (Tijero et al., 2013), and less cognitive decline (Saunders-Pullman et al., 2018; D’Souza and Rajkumar, 2020).