Recently, Meloni et al. (2023) showed that L1CAM-positive neuronal EVs contained elevated levels of oligomeric α-synuclein in PD compared to atypical Parkinsonian syndromes while Tau aggregates showed the opposite trend, demonstrating good classification power for PD, progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Here, L1CAM is linked to Parkinson disease.