On the one hand loss of this domain prevents dimer formation and reduces the neurotoxicity of LRRK2 [62], but on the other hand, low resolution structural studies of dimeric full-length LRRK2 do not position the two WD40 domains in sufficiently close proximity to interact [53], while PD-associated WD40 domain variants that lie within the dimerisation interface weaken interaction between isolated WD40 domains [63]. Here, LRRK2 is linked to Parkinson disease.