Since 1997, with the discovery of the Parkinson’s disease-causing Ala53Thr variant in SNCA, the gene that encodes α-synuclein,1 our understanding of this common neurodegenerative disease has fundamentally changed, mainly due to a large number of genetic discoveries over the past 25 years. This journey is extensively and elegantly summarised by Shen-Yang Lim and colleagues in their Personal View in The Lancet Neurology.2