One possibility is that the effect of LRRK2 on α-Syn may take place via the modulation of other key proteins, such as Rab GTPases or other kinases, which affect pathways involved in the degradation of α-Syn, and the propagation of pathology as well, resulting in PD-associated features, for example the appearance of typical α-synuclein Lewy-bodies (Outeiro et al., 2019). Here, SNCA is linked to Parkinson disease.