Proteomic biomarkers in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder that affects movement and is caused by the death of the dopaminergic neurons in the compact part of the substantia nigra. Its diagnosis is essentially clinical, but although the signs and symptoms of PD are well known, the rate of diagnostic error is relatively high. It is estimated that 10-30% of patients initially diagnosed with PD are later reclassified. This disease has a high prevalence beyond the age of 60, and one of its biggest problems is that it is diagnosed when the degenerative process is already at a very advanced stage. Therefore, it is necessary to look for other biomarkers that make it possible to carry out an early diagnosis of PD, follow up its development, distinguish it from other related pathologies (parkinsonisms) and help monitor the effect of novel therapies. The fact that there are mutations that lead to PD, as well as polygenetic combinations that can act as risk factors, suggests the possibility of measuring the proteins resulting from the expression of these genes in peripheral tissues. And once their sensitivity and specificity have been proved they could be used as biomarkers for PD, even in the early phases of the disease. The aim of this work is to focus on a detailed review of the main candidate proteomic biomarkers researched to date by discussing the most recent literature.