Cerebrospinal fluid (CSF) α-synuclein assays by real-time quacking-induced conversion (Rt-QuIC) were positive in 90% of 52 iRBD patients and 10% of 40 controls, being diagnosed with PD 62% of iRBD patients after 7.1 years of follow-up [142]. This evidence concerns the gene SNCA and Parkinson disease.