RASD2 and Parkinson disease: Moreover, in contrast to the experimental models of DA neuron degeneration based on toxic insults, in which a toxin is injected locally in different basal ganglia structures, the Rhes KO animal model might provide new insights into the basal ganglia structures more vulnerable to DA neuron degeneration and might help in clarifying the mechanism of idiopathic PD, where the mechanism of neurodegeneration of DA neurons is still unclear.