SLC6A3 and frontotemporal dementia: However, the data from this dataset (PPMI) have been widely validated78,79 and the striatal binding ratios of healthy controls are consistent with those of reference studies18,19 and with those of the European multicentre database of healthy controls for 123I-Ioflupane SPECT.45 Another limitation is the focus on the dopamine transporter levels in the putamen and caudate, which may not capture the whole spectrum of dopaminergic dysfunction in FTD.