Aberrant α-synuclein (α-Syn) aggregation, which may be caused by genetic and environmental factors, plays a central role in the pathogenesis of synucleinopathies, including Parkinson’s disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA; Spillantini et al., 1997; Goedert, 2001; Stefanis, 2012; Villar-Piqué et al., 2016; Wong and Krainc, 2017; Mehra et al., 2019). The gene discussed is SNCA; the disease is Lewy body dementia.