SNCA and Parkinson disease: Parkinson’s disease (PD) is thesecond most common neurodegenerativedisease after Alzheimer’s disease,1 affecting several million people worldwide.2,3 Thetypical pathological hallmark is the accumulation of fibrillar proteininclusions, know as Lewy bodies (LBs) and Lewy neurites (LNs) in thebrain.4,5 The major component of LBs and LNs is fibrillarforms of the human α-synuclein (AS) protein.3,6 ASis a 140 amino acid disordered conformational ensembleboth in aqueous solution and in vivo.