Christine Klein

Pathogenic variants in PRKN cause early‐onset Parkinson's disease (PD), while the role of alpha‐synuclein in PRKN ‐PD remains uncertain. One study performed a blood‐based alpha‐synuclein seed amplification assay (SAA) in PRKN ‐PD, not detecting seed amplification in 17 PRKN ‐PD patients. By applying a methodologically different SAA focusing on neuron‐derived extracellular vesicles, we demonstrated alpha‐synuclein seed amplification in 8 of 13 PRKN ‐PD patients, challenging the view of PRKN ‐PD as a non‐synucleinopathy. Moreover, we performed blinded replication of the neuron‐derived extracellular vesicles‐dependent SAA in idiopathic PD patients and healthy controls. In conclusion, blood‐based neuron‐derived extracellular vesicles‐dependent SAA represents a promising biomarker to elucidate the underpinnings of (monogenic) PD. ANN NEUROL 2024

Background Alterations in mitochondrial dysfunction have been implicated in the pathogenesis of Parkinson's disease (PD). Mitochondrial energy production is linked to glucose metabolism, and diabetes is associated with PD. However, studies investigating glucose metabolism in vivo in genetically stratified PD patients and controls have yet to be performed. Objectives The objectives of this study were to explore glucose production, gluconeogenesis, and the contribution of gluconeogenesis to glucose production in idiopathic and PRKN PD compared with healthy controls with state‐of‐the‐art biochemical methods. Methods We applied a dried‐blood sampling/gas chromatography/mass spectrometry approach to monitor fluxes in the Cori cycle in vivo. Results The contribution of gluconeogenesis to total glucose production is increased in idiopathic PD patients (n = 33), but not in biallelic PRKN mutation carriers (n = 5) compared with healthy controls (n = 13). Conclusions We provide first‐time in vivo evidence for alterations in glucose metabolism in idiopathic PD, in keeping with the epidemiological evidence for an association between PD and diabetes. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.