Our observations of Parkinson-like deficits in our INCL model provided a rationale for assessing nigrostriatal DA involvement in these movement impairments of the Cln1−/− mouse by quantifying levels of TH in the substantia nigra as well as levels of DA, DOPAC, HVA, TH, and DAT in the corpus striatum. This evidence concerns the gene SLC6A3 and Parkinsonism.