The composite α-synuclein and clusterin measurement exhibited an improved AUC, sensitivity and specificity estimates for differential diagnosis in predicting clinical PD versus other proteinopathies, with an AUC=0.98 (sensitivity 0.94; specificity 0.96), even in the prodromal phase of PD (RBD vs other proteinopathies, AUC=0.98, sensitivity 0.95, specificity 0.93) as shown in figure 3D, F and online supplementary table 2. This evidence concerns the gene CLU and Parkinson disease.