Table 2.

Parkinson’s Disease and circulating miRNAs.

miRNA	Sample	Experimental approach	Pilot study	Validation study	Reference
18 significantly under-expressed miRNAs	PBMC	miRNA profiling	Microarray PD: 19 CT: 13		[57]
miR-1, miR-22-5p and miR-29 distinguish non-treated PD from healthy subjects	Total peripheral blood	miRNA profiling	qRT-PCR untreated PD: 8 treated PD: 4 early-onset PD: 7 CT: 8		[58]
miR-16-2-3p, miR-26a-2-3p, miR30a differentiate treated from untreated patients	Total peripheral blood	miRNA profiling	qRT-PCR untreated PD: 8 treated PD: 4 early-onset PD: 7 CT: 8		[58]
miR-331-5p upregulated	Plasma	miRNA profiling	Taqman® miRNA qRT-PCR PD: 31 CT: 25		[59]
miR-1826, miR-450b-3p, miR-626, and miR-505	Plasma	miRNA profiling	Agilent microarray PD: 32 CT: 32	Taqman® miRNA qRT-PCR treated PD: 20 untreated PD: 10 PSP: 5 MSA: 4 CT: 4	[60]
16 miRNAs (including miR-16, miR-20a and miR-320) modified in patients pre-DBS	Leukocytes	miRNA profiling	Next Generation Sequencing PD pre-DBS: 3 PD post-DBS: 3 CT: 6		[61]

(PD: Parkinson Disease; PSP: Progressive Supranuclear Palsy; MSA: Multiple System Atrophy; DBS: Deep Brain Stimulation).