In another study, this group detected an early loss of kinesin protein (anterograde transport motor protein) in the putamen of PD patients (H&Y stage 1 and 2), representing axonal loss, while reductions of typical cytoplasmic proteins like dynein light chain Tctex 3 as well as TH protein levels in the SN were only observed at later PD stages (Chu et al., 2012). This evidence concerns the gene TH and Parkinson disease.