1. A method of classifying a sample of a patient suffering from or at risk of developing Parkinson's Disease, wherein said sample is a blood sample, said method comprising the steps of: a) determining in said sample an expression level of at least one miRNA selected from the group consisting of miRNAs having the sequence SEQ ID NO 69, SEQ ID NO 142, SEQ ID NO 2, SEQ ID NO 59, SEQ ID NO 58 and SEQ ID NO 65; b) comparing the pattern of expression level(s) determined in step a) with one or several reference pattern(s) of expression levels; and c) classifying the sample of said patient from the outcome of the comparison in step b) into one of at least two classes.