The present invention is the protein of melanotransferrin, or an encoding nucleic acid of same, for use in the diagnosis of Parkinsons disease (PD). The invention is a method of diagnosis of PD in a subject, comprising assessing the level of melanotransferrin in the saliva or in a saliva sample of said subject and determining whether said level is above or below a value of 8.6 µg/ml, wherein a value below 8.6 µg/ml is indicative of PD. Another aspect is a kit comprising at least one reagent, preferably an antibody, for the quantification of melanotransferrin in the saliva or in a saliva sample of a subject enabling the comparison of said quantification with a predetermined cut-off value.
