No Correlation between Plasma GPNMB Levels and Multiple System Atrophy in Chinese Cohorts

Abstract Background Glycoprotein nonmetastatic melanoma protein B (GPNMB) has been demonstrated to mediate pathogenicity in Parkinson's disease (PD) through interactions with α‐synuclein, and plasma GPNMB tended to be a novel biomarker for PD. Objective The goal of this study was to investigate whether plasma GPNMB could act as a potential biomarker for the clinical diagnosis and severity monitoring of multiple system atrophy (MSA), another typical synucleinopathy. Methods Plasma GPNMB levels in patients with MSA, patients with PD, and healthy control subjects (HCs) were quantified using enzyme‐linked immunosorbent assays. Results A total of 204 patients with MSA, 65 patients with PD, and 207 HCs were enrolled. The plasma GPNMB levels in patients with MSA were similar to those in HCs ( P = 0.251) but were significantly lower than those in patients with PD ( P = 0.003). Moreover, there was no significant correlation detected between the plasma GPNMB levels and disease severity scores of patients with MSA. Conclusions No evidence was detected for the biomarker potential of plasma GPNMB in MSA. © 2023 International Parkinson and Movement Disorder Society.