Genetic factors can affect the risk for PD and mutations in several genes, such as SNCA (the gene encoding α‐syn), LRRK2, Parkin and PINK 1, causing either dominant or recessive forms of PD (Moore et al., 2005), while multiplications of SNCA cause either PD or DLB (reviewed in [Rosborough et al., 2017]). Here, LRRK2 is linked to Parkinson disease.