Very interestingly, the neuropathological examination of a human PD patient who had been continuously infused with GDNF for 43 weeks into the right putamen revealed a clear increase in GAP-43 labeling at the ipsilateral side being associated with an improvement in the clinical UPDRS score and an increased 18F-dopa uptake in the ipsilateral posterior putamen (Love et al., 2005). Here, GAP43 is linked to Parkinson disease.