Synucleinopathies are a group of neurodegenerative diseases caused by the abnormal accumulation α-synuclein, a protein normally found in the brain and neurons. Incorrect folding of α-synuclein leads to formation of “seeds,” which attract more α-synuclein proteins to form larger clumps. Although, α-synuclein seeds have been found in various tissues and blood of patients with synucleinopathies, its potential as a biomarker is ambiguous. Recently, in a study published in Nature Medicine, Associate Professor Ayami Okuzumi along with Senior Associate Professor Taku Hatano, both from the Juntendo University School of Medicine, Senior Assistant Professor Gen Matsumoto at the Nagasaki University School of Medicine, and Professor Nobutaka Hattori from Juntendo University Faculty of Medicine /RIKEN Center for Brain Science, present a novel assay that can efficiently detect α-synuclein seeds from a patient’s serum.