α-syn and SNP rs356219 as a potential biomarker in blood for Parkinson’s disease in Mexican Mestizos

•Combination of plasmatic α-synuclein and SNP rs356219 could be useful as a multi-modal biomarker for Parkinson’s disease.•The blood biomarker can discriminate Parkinson’s disease patients from healthy subjects.•The blood biomarker identifies Parkinson’s disease at early stages. Clinical criteria diagnose Parkinson's disease (PD), therefore, it is crucial to find biological elements that could support diagnosis or even act as prognostic tools of PD. The SNCA gene codifies a protein called α - synuclein; several studies associate genetic and biochemical factors of SNCA with PD, including transcript and plasmatic protein levels, however, contradictory evidence indicates inconclusive results. We aim to compare SNCA mRNA expression, plasmatic α-syn protein and rs356219 SNP between PD cases and a control group, and to identify a potential biomarker in Mexican mestizos', focusing on these three components determined in blood. We included 88 PD patients and 88 age-matched controls. We observed higher α-syn protein and decreased SNCA mRNA levels in PD subjects, compared to control group (p = 0.044 and p