The presence of a direct link between GBA1 mutations and synucleinopathies such as PD and dementia with Lewy bodies (LBD) has been uncovered by multicenter genetic studies (Sidransky 2005; Sidransky et al. 2009; Goker-Alpan et al. 2004, 2008, 2012; reviewed in Aflaki et al. 2017). Here, GBA1 is linked to Parkinson disease.