SNCA and Parkinson disease: Interestingly, patients with rare dominantly inherited mutations in α-synuclein, or α-synuclein triplications, present with severe cognitive and psychiatric symptoms (Polymeropoulos et al., 1997; Spira et al., 2001; Singleton et al., 2003; Kiely et al., 2013; Lesage et al., 2013) and maybe more accurately described as DLB patients rather than PD.