Association between microRNA 155 gene polymorphism and sporadic Parkinson’s disease

INTRODUCTION: The functional single nucleotide polymorphism (SNP) rs767649 in the miR-155 gene has been linked to other neurological disorders, but its association with sporadic Parkinson's disease (PD) remains unclear. METHODS: The rs767649 SNP was genotyped via TaqMan assay. Serum miR-155 levels were measured by RT-qPCR. Statistical analyses included ROC analysis for assessing diagnostic value, Pearson correlation analysis with clinical scores (UPDRS-III, H-Y staging, MoCA), and logistic regression for identifying risk factors of PD. RESULTS: The miR-155 rs767649 A allele served as a protective factor against PD, with AA homozygotes showing the lowest risk. The TT genotype was associated with elevated serum miR‑155, greater motor impairment (UPDRS‑III, H‑Y stage), and reduced cognitive function (MoCA) in PD patients when compared to TA or AA carriers. In PD patients, elevated serum miR-155 levels correlated with disease severity, distinguished patients from healthy controls, and emerged as an independent risk factor for PD. CONCLUSION: The miR-155 rs767649 polymorphism might affect PD susceptibility, and its A allele potentially exerted a protective effect against PD in Han Chinese population. Elevated miR-155 levels appear to be correlated with disease severity and may be an independent risk factor, suggesting its potential as a biomarker for PD diagnosis.