Circulating serum cell-free dna biomarkers and methods

A method for treating Parkinson's disease in a human patient, comprising the steps of:

• obtaining a sample from said human patient, said sample being serum or plasma;
• and
• identifying differential levels of at least one of SEQ ID NOS:
• 24 and 89 within said sample compared to those of a healthy control;
• diagnosing the human patient as having Parkinson's disease based on the detection of differential levels of at least 2.275 and 1.842 fold, respectively, in the sample above that of the healthy control for the identified sequence among SEQ ID NOS:
• 24 and 89;
• and
• administering L-dopa therapy to the human patient diagnosed as having Parkinson's disease.