In a paper published in the high profile journal Lancet Neurology, a group of Parkinson's researchers including our member Günter Höglinger, propose a biologically-based, three-part classification for Parkinson's disease (PD) ("S-N-G" system, SynNeurGe) in line with today's knowledge of the complex pathomechanisms and biological heterogeneity. On the promising path of developing disease-modifying or causal therapies, exact classification and stratification is essential to facilitate meaningful study results.