GAK and multiple system atrophy: However, variability in LRRK2 (leucine-rich repeat kinase 2), GAK (cyclin G-associated kinase) and MAPT (microtubule-associated protein tau) has been also implicated, with variants in SNCA and MAPT found to represent also risk factors for MSA (Scholz et al., 2009; Simon-Sanchez et al., 2009; Vilarino-Guell et al., 2011).