SNCA and Parkinson disease: Idiopathic RBD, characterized by loss of normal atonia during REM sleep, is considered a risk factor for Parkinson’s disease and other synucleinopathies: over 80% of idiopathic RBD patients may eventually develop a neurodegenerative disorder linked to α-synuclein accumulation in the brain (Iranzo et al., 2013; Schenck et al., 2013).